DISINFECTIONin Health Care

DrTVRao MD

What is Disinfection

bullDisinfectants are substances that are applied to non-living objects to destroy microorganisms that are living on the objects Disinfection does not necessarily kill all microorganisms especially resistant bacterial spores it is less effective than sterilization which is an extreme physical andor chemical process that kills all types of life

A tribute to Ignaz Semmelweis

A Hygienic and Scientific Hand Washing continues to be best prayer in the Hospital

Defining What is Disinfection

bullDisinfection may be defined as Cleaning an article of some or all of the pathogenic organisms which may cause infection

bull Perfect disinfectant would also offer complete and full sterilization without harming other forms of life be inexpensive and non-corrosive Unfortunately ideal disinfectants do not exist Most disinfectants are also by their very nature potentially harmful (even toxic) to humans or animals

TerminologybullAntisepsis chemical destruction of vegetative pathogens on living tissue

bullDegerming mechanical removal of microbes from limited area

bullSanitization lowering microbial counts on eating and drinking utensils to safe levels

TerminologybullBiocide or germicide kills microorganisms

bullFungicide kills fungi

bullViricide inactivates viruses

bullBacteriostatic agent stops growth of bacteria

Terminologybull Sepsis bacterial

contamination

bull Asepsis absence of significant contamination

bull Aseptic techniqueminimizes contamination

Antiseptics versus

DisinfectantsAntisepticsUse on skin and mucous membranes to kill

microorganismsNot for use on inanimate objectsDisinfectants

Use to kill microorganisms on inanimate objects

Not for use on skin or mucous membranes

High-level versus low-level disinfectants

Chemical Methodsbull Disinfectants and

antiseptics

bull Surface-active agents (surfactants)

bull Chemical food preservatives

bull Aldehydes

bull Gas sterilization

bull Oxidizing agents

bull [Antibiotics]

Chemicals ndash Disinfection

bull Antiseptics - chemicals that kill microorganisms on living skin or mucous membranes

bull Bactericidal - chemical agents capable of killing bacteria Similarly agents that are virucidal fungicidal or sporicidal are agents capable of killing these organisms

bull Bacteriostatic - Chemical agents that inhibit the growth of bacteria but do not necessarily kill them

Disinfectantsbull Killinhibit growth of

microbes on surfaces

bull Phenols and phenolic damage lipid membranes

bull Active in presence of organic matter

bull Stablebull Persist for long

periods after application

AntisepticsbullBiguanides Chlorhexidine

bullLow toxicitybullUsed on skin and mucous membranes

Cleaning bull Cleaning - the physical removal of foreign material

eg dust soil organic material such as blood secretions excretions and microorganisms Cleaning generally removes rather than kills microorganisms It is accomplished with water detergents and mechanical action The terms ldquodecontaminationrdquo and ldquosanitationrdquo may be used for this process in certain settings eg central service or dietetics Cleaning reduces or eliminates the reservoirs of potential pathogenic organisms

Decontaminationbull Decontamination

the removal of disease-producing microorganisms to leave an item safe for further handling

Disinfectionbull Disinfection the inactivation of disease-

producing microorganisms Disinfection does not destroy bacterial spores Disinfectants are used on inanimate objects in contrast to antiseptics which are used on living tissue Disinfection usually involves chemicals heat or ultraviolet light The nature of chemical disinfection varies with the type of product

High level disinfection bullHigh level disinfection processes

destroy vegetative bacteria mycobacteria fungi and enveloped (lipid) and nonenveloped (non lipid) viruses but not necessarily bacterial spores High level disinfectant chemicals (also called chemical sterilants) must be capable of sterilization when contact time is extended Items must be thoroughly cleaned prior to high level disinfection

Intermediate level disinfection

bull Intermediate level disinfectants kill vegetative bacteria most viruses and most fungi but not resistant bacterial spores

Low level disinfection bullLow level disinfectants kill most vegetative bacteria and some fungi as well as enveloped (lipid) viruses (eg hepatitis B C hantavirus and HIV) Low level disinfectants do not kill mycobacteria or bacterial spores Low level disinfectants are typically used to clean environmental surfaces

AntisepticsbullBiguanides Chlorhexidine

bullLow toxicitybullUsed on skin and mucous membranes

AntisepticsbullAlcohol protein

denaturation and membrane damagebull evaporate quicklybull ethanol and

isopropanolbull [not effective if

taken internally]

Disinfectantsbull Halogens iodine and

chlorinebull Iodine used in

solution Betadineregand Isodinereg

bull Chlorine is a gas that forms bleach (hypochlorite) in water

bull Chloramines are chlorine and ammonia

Selection and Use of Disinfectants

Sterilization ndash An absolute Procedure

bull The destruction of all forms of microbial life including bacteria viruses spores and fungi Items should be cleaned thoroughly before effective sterilization can take place

Noncritical itemsbull That either come in

contact with only intact skin but not mucous membranes or do not directly contact the patient Reprocessing of noncritical items involves cleaning andor low level disinfection

Sanitation bull Process that

reduces microorganisms on an inanimate object to a level below that of infectious hazard (eg dishes and eating utensils are sanitized

Semi critical items bull Devices that come in

contact with no intact skin or mucous membranes but ordinarily do not penetrate them Reprocessing semi critical items involves meticulous cleaning followed preferably by high-level disinfection

Disinfectant effectiveness depends on many factors

bull Type of contaminating microorganism Each disinfectant has unique antimicrobial attributes

bull bull Degree of contamination This determines the quality of disinfectant required and time of exposure

bull bull Amount of proteinaceous material present High protein based materials absorb and neutralize some chemical disinfectants

bull bull Presence of organic matter and other compounds such as soaps may neutralize some disinfectants

bull bull Chemical nature of disinfectant It is important to understand the mode of action in order to select the appropriate disinfectant

Disinfectant effectiveness depends on many factors

bull Concentration and quantity of disinfectant It is important to choose the proper concentration and quantity of disinfectant that is best suited to each situation

bull bull Contact time and temperature Sufficient time and appropriate temperature must be allowed for action of the disinfectant and may depend on the degree of contamination and organic matter load

bull bull Residual activity and effects on fabric and metal should be considered for specific situations

bull bull Application temperature pH and interactions with other compounds must be considered

bull bull Toxicity to the environment and relative safety to people that may be exposed

bullbull Cost An important factor

bull 5

Microbial Characteristics and Microbial Control

Figure 711

PHENOLICS

bull Examples Benzyl-4-chlorophenol Amyl phenol Phenyl phenol

bullAdvantages and disadvantages good general purpose disinfectants not readily inactivated

bullby organic matter active against wide range of organisms (including mycobacterium) but not sporicidal

Phenol as Disinfectant bull Phenolic disinfectants

are effective against bacteria (especially gram positive bacteria) and enveloped viruses They are not effective against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material

Phenol as Disinfectantbull They are not effective

against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material This class of compounds is used for decontamination of the hospital environment including laboratory surfaces and noncritical medical items

Phenol as Disinfectantbull Phenolics are not

recommended for semi critical items because of the lack of validated efficacy data for many of the available formulations and because the residual disinfectant on porous materials may cause tissue irritation even when thoroughly rinsed

Alcohols bull ldquoAlcohol refers to two water-soluble

chemicals ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria (Gram + and Gram -) they also are tuberculocidal fungicidal and virucidal against enveloped viruses Alcohols are not effective against bacterial spores and have limited effectiveness against nonenveloped viruses

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

What is Disinfection

bullDisinfectants are substances that are applied to non-living objects to destroy microorganisms that are living on the objects Disinfection does not necessarily kill all microorganisms especially resistant bacterial spores it is less effective than sterilization which is an extreme physical andor chemical process that kills all types of life

A tribute to Ignaz Semmelweis

A Hygienic and Scientific Hand Washing continues to be best prayer in the Hospital

Defining What is Disinfection

bullDisinfection may be defined as Cleaning an article of some or all of the pathogenic organisms which may cause infection

bull Perfect disinfectant would also offer complete and full sterilization without harming other forms of life be inexpensive and non-corrosive Unfortunately ideal disinfectants do not exist Most disinfectants are also by their very nature potentially harmful (even toxic) to humans or animals

TerminologybullAntisepsis chemical destruction of vegetative pathogens on living tissue

bullDegerming mechanical removal of microbes from limited area

bullSanitization lowering microbial counts on eating and drinking utensils to safe levels

TerminologybullBiocide or germicide kills microorganisms

bullFungicide kills fungi

bullViricide inactivates viruses

bullBacteriostatic agent stops growth of bacteria

Terminologybull Sepsis bacterial

contamination

bull Asepsis absence of significant contamination

bull Aseptic techniqueminimizes contamination

Antiseptics versus

DisinfectantsAntisepticsUse on skin and mucous membranes to kill

microorganismsNot for use on inanimate objectsDisinfectants

Use to kill microorganisms on inanimate objects

Not for use on skin or mucous membranes

High-level versus low-level disinfectants

Chemical Methodsbull Disinfectants and

antiseptics

bull Surface-active agents (surfactants)

bull Chemical food preservatives

bull Aldehydes

bull Gas sterilization

bull Oxidizing agents

bull [Antibiotics]

Chemicals ndash Disinfection

bull Antiseptics - chemicals that kill microorganisms on living skin or mucous membranes

bull Bactericidal - chemical agents capable of killing bacteria Similarly agents that are virucidal fungicidal or sporicidal are agents capable of killing these organisms

bull Bacteriostatic - Chemical agents that inhibit the growth of bacteria but do not necessarily kill them

Disinfectantsbull Killinhibit growth of

microbes on surfaces

bull Phenols and phenolic damage lipid membranes

bull Active in presence of organic matter

bull Stablebull Persist for long

periods after application

AntisepticsbullBiguanides Chlorhexidine

bullLow toxicitybullUsed on skin and mucous membranes

Cleaning bull Cleaning - the physical removal of foreign material

eg dust soil organic material such as blood secretions excretions and microorganisms Cleaning generally removes rather than kills microorganisms It is accomplished with water detergents and mechanical action The terms ldquodecontaminationrdquo and ldquosanitationrdquo may be used for this process in certain settings eg central service or dietetics Cleaning reduces or eliminates the reservoirs of potential pathogenic organisms

Decontaminationbull Decontamination

the removal of disease-producing microorganisms to leave an item safe for further handling

Disinfectionbull Disinfection the inactivation of disease-

producing microorganisms Disinfection does not destroy bacterial spores Disinfectants are used on inanimate objects in contrast to antiseptics which are used on living tissue Disinfection usually involves chemicals heat or ultraviolet light The nature of chemical disinfection varies with the type of product

High level disinfection bullHigh level disinfection processes

destroy vegetative bacteria mycobacteria fungi and enveloped (lipid) and nonenveloped (non lipid) viruses but not necessarily bacterial spores High level disinfectant chemicals (also called chemical sterilants) must be capable of sterilization when contact time is extended Items must be thoroughly cleaned prior to high level disinfection

Intermediate level disinfection

bull Intermediate level disinfectants kill vegetative bacteria most viruses and most fungi but not resistant bacterial spores

Low level disinfection bullLow level disinfectants kill most vegetative bacteria and some fungi as well as enveloped (lipid) viruses (eg hepatitis B C hantavirus and HIV) Low level disinfectants do not kill mycobacteria or bacterial spores Low level disinfectants are typically used to clean environmental surfaces

AntisepticsbullBiguanides Chlorhexidine

bullLow toxicitybullUsed on skin and mucous membranes

AntisepticsbullAlcohol protein

denaturation and membrane damagebull evaporate quicklybull ethanol and

isopropanolbull [not effective if

taken internally]

Disinfectantsbull Halogens iodine and

chlorinebull Iodine used in

solution Betadineregand Isodinereg

bull Chlorine is a gas that forms bleach (hypochlorite) in water

bull Chloramines are chlorine and ammonia

Selection and Use of Disinfectants

Sterilization ndash An absolute Procedure

bull The destruction of all forms of microbial life including bacteria viruses spores and fungi Items should be cleaned thoroughly before effective sterilization can take place

Noncritical itemsbull That either come in

contact with only intact skin but not mucous membranes or do not directly contact the patient Reprocessing of noncritical items involves cleaning andor low level disinfection

Sanitation bull Process that

reduces microorganisms on an inanimate object to a level below that of infectious hazard (eg dishes and eating utensils are sanitized

Semi critical items bull Devices that come in

contact with no intact skin or mucous membranes but ordinarily do not penetrate them Reprocessing semi critical items involves meticulous cleaning followed preferably by high-level disinfection

Disinfectant effectiveness depends on many factors

bull Type of contaminating microorganism Each disinfectant has unique antimicrobial attributes

bull bull Degree of contamination This determines the quality of disinfectant required and time of exposure

bull bull Amount of proteinaceous material present High protein based materials absorb and neutralize some chemical disinfectants

bull bull Presence of organic matter and other compounds such as soaps may neutralize some disinfectants

bull bull Chemical nature of disinfectant It is important to understand the mode of action in order to select the appropriate disinfectant

Disinfectant effectiveness depends on many factors

bull Concentration and quantity of disinfectant It is important to choose the proper concentration and quantity of disinfectant that is best suited to each situation

bull bull Contact time and temperature Sufficient time and appropriate temperature must be allowed for action of the disinfectant and may depend on the degree of contamination and organic matter load

bull bull Residual activity and effects on fabric and metal should be considered for specific situations

bull bull Application temperature pH and interactions with other compounds must be considered

bull bull Toxicity to the environment and relative safety to people that may be exposed

bullbull Cost An important factor

bull 5

Microbial Characteristics and Microbial Control

Figure 711

PHENOLICS

bull Examples Benzyl-4-chlorophenol Amyl phenol Phenyl phenol

bullAdvantages and disadvantages good general purpose disinfectants not readily inactivated

bullby organic matter active against wide range of organisms (including mycobacterium) but not sporicidal

Phenol as Disinfectant bull Phenolic disinfectants

are effective against bacteria (especially gram positive bacteria) and enveloped viruses They are not effective against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material

Phenol as Disinfectantbull They are not effective

against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material This class of compounds is used for decontamination of the hospital environment including laboratory surfaces and noncritical medical items

Phenol as Disinfectantbull Phenolics are not

recommended for semi critical items because of the lack of validated efficacy data for many of the available formulations and because the residual disinfectant on porous materials may cause tissue irritation even when thoroughly rinsed

Alcohols bull ldquoAlcohol refers to two water-soluble

chemicals ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria (Gram + and Gram -) they also are tuberculocidal fungicidal and virucidal against enveloped viruses Alcohols are not effective against bacterial spores and have limited effectiveness against nonenveloped viruses

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

A tribute to Ignaz Semmelweis

A Hygienic and Scientific Hand Washing continues to be best prayer in the Hospital

Defining What is Disinfection

bullDisinfection may be defined as Cleaning an article of some or all of the pathogenic organisms which may cause infection

bull Perfect disinfectant would also offer complete and full sterilization without harming other forms of life be inexpensive and non-corrosive Unfortunately ideal disinfectants do not exist Most disinfectants are also by their very nature potentially harmful (even toxic) to humans or animals

TerminologybullAntisepsis chemical destruction of vegetative pathogens on living tissue

bullDegerming mechanical removal of microbes from limited area

bullSanitization lowering microbial counts on eating and drinking utensils to safe levels

TerminologybullBiocide or germicide kills microorganisms

bullFungicide kills fungi

bullViricide inactivates viruses

bullBacteriostatic agent stops growth of bacteria

Terminologybull Sepsis bacterial

contamination

bull Asepsis absence of significant contamination

bull Aseptic techniqueminimizes contamination

Antiseptics versus

DisinfectantsAntisepticsUse on skin and mucous membranes to kill

microorganismsNot for use on inanimate objectsDisinfectants

Use to kill microorganisms on inanimate objects

Not for use on skin or mucous membranes

High-level versus low-level disinfectants

Chemical Methodsbull Disinfectants and

antiseptics

bull Surface-active agents (surfactants)

bull Chemical food preservatives

bull Aldehydes

bull Gas sterilization

bull Oxidizing agents

bull [Antibiotics]

Chemicals ndash Disinfection

bull Antiseptics - chemicals that kill microorganisms on living skin or mucous membranes

bull Bactericidal - chemical agents capable of killing bacteria Similarly agents that are virucidal fungicidal or sporicidal are agents capable of killing these organisms

bull Bacteriostatic - Chemical agents that inhibit the growth of bacteria but do not necessarily kill them

Disinfectantsbull Killinhibit growth of

microbes on surfaces

bull Phenols and phenolic damage lipid membranes

bull Active in presence of organic matter

bull Stablebull Persist for long

periods after application

AntisepticsbullBiguanides Chlorhexidine

bullLow toxicitybullUsed on skin and mucous membranes

Cleaning bull Cleaning - the physical removal of foreign material

eg dust soil organic material such as blood secretions excretions and microorganisms Cleaning generally removes rather than kills microorganisms It is accomplished with water detergents and mechanical action The terms ldquodecontaminationrdquo and ldquosanitationrdquo may be used for this process in certain settings eg central service or dietetics Cleaning reduces or eliminates the reservoirs of potential pathogenic organisms

Decontaminationbull Decontamination

the removal of disease-producing microorganisms to leave an item safe for further handling

Disinfectionbull Disinfection the inactivation of disease-

producing microorganisms Disinfection does not destroy bacterial spores Disinfectants are used on inanimate objects in contrast to antiseptics which are used on living tissue Disinfection usually involves chemicals heat or ultraviolet light The nature of chemical disinfection varies with the type of product

High level disinfection bullHigh level disinfection processes

destroy vegetative bacteria mycobacteria fungi and enveloped (lipid) and nonenveloped (non lipid) viruses but not necessarily bacterial spores High level disinfectant chemicals (also called chemical sterilants) must be capable of sterilization when contact time is extended Items must be thoroughly cleaned prior to high level disinfection

Intermediate level disinfection

bull Intermediate level disinfectants kill vegetative bacteria most viruses and most fungi but not resistant bacterial spores

Low level disinfection bullLow level disinfectants kill most vegetative bacteria and some fungi as well as enveloped (lipid) viruses (eg hepatitis B C hantavirus and HIV) Low level disinfectants do not kill mycobacteria or bacterial spores Low level disinfectants are typically used to clean environmental surfaces

AntisepticsbullBiguanides Chlorhexidine

bullLow toxicitybullUsed on skin and mucous membranes

AntisepticsbullAlcohol protein

denaturation and membrane damagebull evaporate quicklybull ethanol and

isopropanolbull [not effective if

taken internally]

Disinfectantsbull Halogens iodine and

chlorinebull Iodine used in

solution Betadineregand Isodinereg

bull Chlorine is a gas that forms bleach (hypochlorite) in water

bull Chloramines are chlorine and ammonia

Selection and Use of Disinfectants

Sterilization ndash An absolute Procedure

bull The destruction of all forms of microbial life including bacteria viruses spores and fungi Items should be cleaned thoroughly before effective sterilization can take place

Noncritical itemsbull That either come in

contact with only intact skin but not mucous membranes or do not directly contact the patient Reprocessing of noncritical items involves cleaning andor low level disinfection

Sanitation bull Process that

reduces microorganisms on an inanimate object to a level below that of infectious hazard (eg dishes and eating utensils are sanitized

Semi critical items bull Devices that come in

contact with no intact skin or mucous membranes but ordinarily do not penetrate them Reprocessing semi critical items involves meticulous cleaning followed preferably by high-level disinfection

Disinfectant effectiveness depends on many factors

bull Type of contaminating microorganism Each disinfectant has unique antimicrobial attributes

bull bull Degree of contamination This determines the quality of disinfectant required and time of exposure

bull bull Amount of proteinaceous material present High protein based materials absorb and neutralize some chemical disinfectants

bull bull Presence of organic matter and other compounds such as soaps may neutralize some disinfectants

bull bull Chemical nature of disinfectant It is important to understand the mode of action in order to select the appropriate disinfectant

Disinfectant effectiveness depends on many factors

bull Concentration and quantity of disinfectant It is important to choose the proper concentration and quantity of disinfectant that is best suited to each situation

bull bull Contact time and temperature Sufficient time and appropriate temperature must be allowed for action of the disinfectant and may depend on the degree of contamination and organic matter load

bull bull Residual activity and effects on fabric and metal should be considered for specific situations

bull bull Application temperature pH and interactions with other compounds must be considered

bull bull Toxicity to the environment and relative safety to people that may be exposed

bullbull Cost An important factor

bull 5

Microbial Characteristics and Microbial Control

Figure 711

PHENOLICS

bull Examples Benzyl-4-chlorophenol Amyl phenol Phenyl phenol

bullAdvantages and disadvantages good general purpose disinfectants not readily inactivated

bullby organic matter active against wide range of organisms (including mycobacterium) but not sporicidal

Phenol as Disinfectant bull Phenolic disinfectants

are effective against bacteria (especially gram positive bacteria) and enveloped viruses They are not effective against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material

Phenol as Disinfectantbull They are not effective

against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material This class of compounds is used for decontamination of the hospital environment including laboratory surfaces and noncritical medical items

Phenol as Disinfectantbull Phenolics are not

recommended for semi critical items because of the lack of validated efficacy data for many of the available formulations and because the residual disinfectant on porous materials may cause tissue irritation even when thoroughly rinsed

Alcohols bull ldquoAlcohol refers to two water-soluble

chemicals ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria (Gram + and Gram -) they also are tuberculocidal fungicidal and virucidal against enveloped viruses Alcohols are not effective against bacterial spores and have limited effectiveness against nonenveloped viruses

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

A Hygienic and Scientific Hand Washing continues to be best prayer in the Hospital

Defining What is Disinfection

bullDisinfection may be defined as Cleaning an article of some or all of the pathogenic organisms which may cause infection

bull Perfect disinfectant would also offer complete and full sterilization without harming other forms of life be inexpensive and non-corrosive Unfortunately ideal disinfectants do not exist Most disinfectants are also by their very nature potentially harmful (even toxic) to humans or animals

TerminologybullAntisepsis chemical destruction of vegetative pathogens on living tissue

bullDegerming mechanical removal of microbes from limited area

bullSanitization lowering microbial counts on eating and drinking utensils to safe levels

TerminologybullBiocide or germicide kills microorganisms

bullFungicide kills fungi

bullViricide inactivates viruses

bullBacteriostatic agent stops growth of bacteria

Terminologybull Sepsis bacterial

contamination

bull Asepsis absence of significant contamination

bull Aseptic techniqueminimizes contamination

Antiseptics versus

DisinfectantsAntisepticsUse on skin and mucous membranes to kill

microorganismsNot for use on inanimate objectsDisinfectants

Use to kill microorganisms on inanimate objects

Not for use on skin or mucous membranes

High-level versus low-level disinfectants

Chemical Methodsbull Disinfectants and

antiseptics

bull Surface-active agents (surfactants)

bull Chemical food preservatives

bull Aldehydes

bull Gas sterilization

bull Oxidizing agents

bull [Antibiotics]

Chemicals ndash Disinfection

bull Antiseptics - chemicals that kill microorganisms on living skin or mucous membranes

bull Bactericidal - chemical agents capable of killing bacteria Similarly agents that are virucidal fungicidal or sporicidal are agents capable of killing these organisms

bull Bacteriostatic - Chemical agents that inhibit the growth of bacteria but do not necessarily kill them

Disinfectantsbull Killinhibit growth of

microbes on surfaces

bull Phenols and phenolic damage lipid membranes

bull Active in presence of organic matter

bull Stablebull Persist for long

periods after application

AntisepticsbullBiguanides Chlorhexidine

bullLow toxicitybullUsed on skin and mucous membranes

Cleaning bull Cleaning - the physical removal of foreign material

eg dust soil organic material such as blood secretions excretions and microorganisms Cleaning generally removes rather than kills microorganisms It is accomplished with water detergents and mechanical action The terms ldquodecontaminationrdquo and ldquosanitationrdquo may be used for this process in certain settings eg central service or dietetics Cleaning reduces or eliminates the reservoirs of potential pathogenic organisms

Decontaminationbull Decontamination

the removal of disease-producing microorganisms to leave an item safe for further handling

Disinfectionbull Disinfection the inactivation of disease-

producing microorganisms Disinfection does not destroy bacterial spores Disinfectants are used on inanimate objects in contrast to antiseptics which are used on living tissue Disinfection usually involves chemicals heat or ultraviolet light The nature of chemical disinfection varies with the type of product

High level disinfection bullHigh level disinfection processes

destroy vegetative bacteria mycobacteria fungi and enveloped (lipid) and nonenveloped (non lipid) viruses but not necessarily bacterial spores High level disinfectant chemicals (also called chemical sterilants) must be capable of sterilization when contact time is extended Items must be thoroughly cleaned prior to high level disinfection

Intermediate level disinfection

bull Intermediate level disinfectants kill vegetative bacteria most viruses and most fungi but not resistant bacterial spores

Low level disinfection bullLow level disinfectants kill most vegetative bacteria and some fungi as well as enveloped (lipid) viruses (eg hepatitis B C hantavirus and HIV) Low level disinfectants do not kill mycobacteria or bacterial spores Low level disinfectants are typically used to clean environmental surfaces

AntisepticsbullBiguanides Chlorhexidine

bullLow toxicitybullUsed on skin and mucous membranes

AntisepticsbullAlcohol protein

denaturation and membrane damagebull evaporate quicklybull ethanol and

isopropanolbull [not effective if

taken internally]

Disinfectantsbull Halogens iodine and

chlorinebull Iodine used in

solution Betadineregand Isodinereg

bull Chlorine is a gas that forms bleach (hypochlorite) in water

bull Chloramines are chlorine and ammonia

Selection and Use of Disinfectants

Sterilization ndash An absolute Procedure

bull The destruction of all forms of microbial life including bacteria viruses spores and fungi Items should be cleaned thoroughly before effective sterilization can take place

Noncritical itemsbull That either come in

contact with only intact skin but not mucous membranes or do not directly contact the patient Reprocessing of noncritical items involves cleaning andor low level disinfection

Sanitation bull Process that

reduces microorganisms on an inanimate object to a level below that of infectious hazard (eg dishes and eating utensils are sanitized

Semi critical items bull Devices that come in

contact with no intact skin or mucous membranes but ordinarily do not penetrate them Reprocessing semi critical items involves meticulous cleaning followed preferably by high-level disinfection

Disinfectant effectiveness depends on many factors

bull Type of contaminating microorganism Each disinfectant has unique antimicrobial attributes

bull bull Degree of contamination This determines the quality of disinfectant required and time of exposure

bull bull Amount of proteinaceous material present High protein based materials absorb and neutralize some chemical disinfectants

bull bull Presence of organic matter and other compounds such as soaps may neutralize some disinfectants

bull bull Chemical nature of disinfectant It is important to understand the mode of action in order to select the appropriate disinfectant

Disinfectant effectiveness depends on many factors

bull Concentration and quantity of disinfectant It is important to choose the proper concentration and quantity of disinfectant that is best suited to each situation

bull bull Contact time and temperature Sufficient time and appropriate temperature must be allowed for action of the disinfectant and may depend on the degree of contamination and organic matter load

bull bull Residual activity and effects on fabric and metal should be considered for specific situations

bull bull Application temperature pH and interactions with other compounds must be considered

bull bull Toxicity to the environment and relative safety to people that may be exposed

bullbull Cost An important factor

bull 5

Microbial Characteristics and Microbial Control

Figure 711

PHENOLICS

bull Examples Benzyl-4-chlorophenol Amyl phenol Phenyl phenol

bullAdvantages and disadvantages good general purpose disinfectants not readily inactivated

bullby organic matter active against wide range of organisms (including mycobacterium) but not sporicidal

Phenol as Disinfectant bull Phenolic disinfectants

are effective against bacteria (especially gram positive bacteria) and enveloped viruses They are not effective against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material

Phenol as Disinfectantbull They are not effective

against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material This class of compounds is used for decontamination of the hospital environment including laboratory surfaces and noncritical medical items

Phenol as Disinfectantbull Phenolics are not

recommended for semi critical items because of the lack of validated efficacy data for many of the available formulations and because the residual disinfectant on porous materials may cause tissue irritation even when thoroughly rinsed

Alcohols bull ldquoAlcohol refers to two water-soluble

chemicals ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria (Gram + and Gram -) they also are tuberculocidal fungicidal and virucidal against enveloped viruses Alcohols are not effective against bacterial spores and have limited effectiveness against nonenveloped viruses

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Defining What is Disinfection

bullDisinfection may be defined as Cleaning an article of some or all of the pathogenic organisms which may cause infection

bull Perfect disinfectant would also offer complete and full sterilization without harming other forms of life be inexpensive and non-corrosive Unfortunately ideal disinfectants do not exist Most disinfectants are also by their very nature potentially harmful (even toxic) to humans or animals

TerminologybullAntisepsis chemical destruction of vegetative pathogens on living tissue

bullDegerming mechanical removal of microbes from limited area

bullSanitization lowering microbial counts on eating and drinking utensils to safe levels

TerminologybullBiocide or germicide kills microorganisms

bullFungicide kills fungi

bullViricide inactivates viruses

bullBacteriostatic agent stops growth of bacteria

Terminologybull Sepsis bacterial

contamination

bull Asepsis absence of significant contamination

bull Aseptic techniqueminimizes contamination

Antiseptics versus

DisinfectantsAntisepticsUse on skin and mucous membranes to kill

microorganismsNot for use on inanimate objectsDisinfectants

Use to kill microorganisms on inanimate objects

Not for use on skin or mucous membranes

High-level versus low-level disinfectants

Chemical Methodsbull Disinfectants and

antiseptics

bull Surface-active agents (surfactants)

bull Chemical food preservatives

bull Aldehydes

bull Gas sterilization

bull Oxidizing agents

bull [Antibiotics]

Chemicals ndash Disinfection

bull Antiseptics - chemicals that kill microorganisms on living skin or mucous membranes

bull Bactericidal - chemical agents capable of killing bacteria Similarly agents that are virucidal fungicidal or sporicidal are agents capable of killing these organisms

bull Bacteriostatic - Chemical agents that inhibit the growth of bacteria but do not necessarily kill them

Disinfectantsbull Killinhibit growth of

microbes on surfaces

bull Phenols and phenolic damage lipid membranes

bull Active in presence of organic matter

bull Stablebull Persist for long

periods after application

AntisepticsbullBiguanides Chlorhexidine

bullLow toxicitybullUsed on skin and mucous membranes

Cleaning bull Cleaning - the physical removal of foreign material

eg dust soil organic material such as blood secretions excretions and microorganisms Cleaning generally removes rather than kills microorganisms It is accomplished with water detergents and mechanical action The terms ldquodecontaminationrdquo and ldquosanitationrdquo may be used for this process in certain settings eg central service or dietetics Cleaning reduces or eliminates the reservoirs of potential pathogenic organisms

Decontaminationbull Decontamination

the removal of disease-producing microorganisms to leave an item safe for further handling

Disinfectionbull Disinfection the inactivation of disease-

producing microorganisms Disinfection does not destroy bacterial spores Disinfectants are used on inanimate objects in contrast to antiseptics which are used on living tissue Disinfection usually involves chemicals heat or ultraviolet light The nature of chemical disinfection varies with the type of product

High level disinfection bullHigh level disinfection processes

destroy vegetative bacteria mycobacteria fungi and enveloped (lipid) and nonenveloped (non lipid) viruses but not necessarily bacterial spores High level disinfectant chemicals (also called chemical sterilants) must be capable of sterilization when contact time is extended Items must be thoroughly cleaned prior to high level disinfection

Intermediate level disinfection

bull Intermediate level disinfectants kill vegetative bacteria most viruses and most fungi but not resistant bacterial spores

Low level disinfection bullLow level disinfectants kill most vegetative bacteria and some fungi as well as enveloped (lipid) viruses (eg hepatitis B C hantavirus and HIV) Low level disinfectants do not kill mycobacteria or bacterial spores Low level disinfectants are typically used to clean environmental surfaces

AntisepticsbullBiguanides Chlorhexidine

bullLow toxicitybullUsed on skin and mucous membranes

AntisepticsbullAlcohol protein

denaturation and membrane damagebull evaporate quicklybull ethanol and

isopropanolbull [not effective if

taken internally]

Disinfectantsbull Halogens iodine and

chlorinebull Iodine used in

solution Betadineregand Isodinereg

bull Chlorine is a gas that forms bleach (hypochlorite) in water

bull Chloramines are chlorine and ammonia

Selection and Use of Disinfectants

Sterilization ndash An absolute Procedure

bull The destruction of all forms of microbial life including bacteria viruses spores and fungi Items should be cleaned thoroughly before effective sterilization can take place

Noncritical itemsbull That either come in

contact with only intact skin but not mucous membranes or do not directly contact the patient Reprocessing of noncritical items involves cleaning andor low level disinfection

Sanitation bull Process that

reduces microorganisms on an inanimate object to a level below that of infectious hazard (eg dishes and eating utensils are sanitized

Semi critical items bull Devices that come in

contact with no intact skin or mucous membranes but ordinarily do not penetrate them Reprocessing semi critical items involves meticulous cleaning followed preferably by high-level disinfection

Disinfectant effectiveness depends on many factors

bull Type of contaminating microorganism Each disinfectant has unique antimicrobial attributes

bull bull Degree of contamination This determines the quality of disinfectant required and time of exposure

bull bull Amount of proteinaceous material present High protein based materials absorb and neutralize some chemical disinfectants

bull bull Presence of organic matter and other compounds such as soaps may neutralize some disinfectants

bull bull Chemical nature of disinfectant It is important to understand the mode of action in order to select the appropriate disinfectant

Disinfectant effectiveness depends on many factors

bull Concentration and quantity of disinfectant It is important to choose the proper concentration and quantity of disinfectant that is best suited to each situation

bull bull Contact time and temperature Sufficient time and appropriate temperature must be allowed for action of the disinfectant and may depend on the degree of contamination and organic matter load

bull bull Residual activity and effects on fabric and metal should be considered for specific situations

bull bull Application temperature pH and interactions with other compounds must be considered

bull bull Toxicity to the environment and relative safety to people that may be exposed

bullbull Cost An important factor

bull 5

Microbial Characteristics and Microbial Control

Figure 711

PHENOLICS

bull Examples Benzyl-4-chlorophenol Amyl phenol Phenyl phenol

bullAdvantages and disadvantages good general purpose disinfectants not readily inactivated

bullby organic matter active against wide range of organisms (including mycobacterium) but not sporicidal

Phenol as Disinfectant bull Phenolic disinfectants

are effective against bacteria (especially gram positive bacteria) and enveloped viruses They are not effective against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material

Phenol as Disinfectantbull They are not effective

against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material This class of compounds is used for decontamination of the hospital environment including laboratory surfaces and noncritical medical items

Phenol as Disinfectantbull Phenolics are not

recommended for semi critical items because of the lack of validated efficacy data for many of the available formulations and because the residual disinfectant on porous materials may cause tissue irritation even when thoroughly rinsed

Alcohols bull ldquoAlcohol refers to two water-soluble

chemicals ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria (Gram + and Gram -) they also are tuberculocidal fungicidal and virucidal against enveloped viruses Alcohols are not effective against bacterial spores and have limited effectiveness against nonenveloped viruses

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

TerminologybullAntisepsis chemical destruction of vegetative pathogens on living tissue

bullDegerming mechanical removal of microbes from limited area

bullSanitization lowering microbial counts on eating and drinking utensils to safe levels

TerminologybullBiocide or germicide kills microorganisms

bullFungicide kills fungi

bullViricide inactivates viruses

bullBacteriostatic agent stops growth of bacteria

Terminologybull Sepsis bacterial

contamination

bull Asepsis absence of significant contamination

bull Aseptic techniqueminimizes contamination

Antiseptics versus

DisinfectantsAntisepticsUse on skin and mucous membranes to kill

microorganismsNot for use on inanimate objectsDisinfectants

Use to kill microorganisms on inanimate objects

Not for use on skin or mucous membranes

High-level versus low-level disinfectants

Chemical Methodsbull Disinfectants and

antiseptics

bull Surface-active agents (surfactants)

bull Chemical food preservatives

bull Aldehydes

bull Gas sterilization

bull Oxidizing agents

bull [Antibiotics]

Chemicals ndash Disinfection

bull Antiseptics - chemicals that kill microorganisms on living skin or mucous membranes

bull Bactericidal - chemical agents capable of killing bacteria Similarly agents that are virucidal fungicidal or sporicidal are agents capable of killing these organisms

bull Bacteriostatic - Chemical agents that inhibit the growth of bacteria but do not necessarily kill them

Disinfectantsbull Killinhibit growth of

microbes on surfaces

bull Phenols and phenolic damage lipid membranes

bull Active in presence of organic matter

bull Stablebull Persist for long

periods after application

AntisepticsbullBiguanides Chlorhexidine

bullLow toxicitybullUsed on skin and mucous membranes

Cleaning bull Cleaning - the physical removal of foreign material

eg dust soil organic material such as blood secretions excretions and microorganisms Cleaning generally removes rather than kills microorganisms It is accomplished with water detergents and mechanical action The terms ldquodecontaminationrdquo and ldquosanitationrdquo may be used for this process in certain settings eg central service or dietetics Cleaning reduces or eliminates the reservoirs of potential pathogenic organisms

Decontaminationbull Decontamination

the removal of disease-producing microorganisms to leave an item safe for further handling

Disinfectionbull Disinfection the inactivation of disease-

producing microorganisms Disinfection does not destroy bacterial spores Disinfectants are used on inanimate objects in contrast to antiseptics which are used on living tissue Disinfection usually involves chemicals heat or ultraviolet light The nature of chemical disinfection varies with the type of product

High level disinfection bullHigh level disinfection processes

destroy vegetative bacteria mycobacteria fungi and enveloped (lipid) and nonenveloped (non lipid) viruses but not necessarily bacterial spores High level disinfectant chemicals (also called chemical sterilants) must be capable of sterilization when contact time is extended Items must be thoroughly cleaned prior to high level disinfection

Intermediate level disinfection

bull Intermediate level disinfectants kill vegetative bacteria most viruses and most fungi but not resistant bacterial spores

Low level disinfection bullLow level disinfectants kill most vegetative bacteria and some fungi as well as enveloped (lipid) viruses (eg hepatitis B C hantavirus and HIV) Low level disinfectants do not kill mycobacteria or bacterial spores Low level disinfectants are typically used to clean environmental surfaces

AntisepticsbullBiguanides Chlorhexidine

bullLow toxicitybullUsed on skin and mucous membranes

AntisepticsbullAlcohol protein

denaturation and membrane damagebull evaporate quicklybull ethanol and

isopropanolbull [not effective if

taken internally]

Disinfectantsbull Halogens iodine and

chlorinebull Iodine used in

solution Betadineregand Isodinereg

bull Chlorine is a gas that forms bleach (hypochlorite) in water

bull Chloramines are chlorine and ammonia

Selection and Use of Disinfectants

Sterilization ndash An absolute Procedure

bull The destruction of all forms of microbial life including bacteria viruses spores and fungi Items should be cleaned thoroughly before effective sterilization can take place

Noncritical itemsbull That either come in

contact with only intact skin but not mucous membranes or do not directly contact the patient Reprocessing of noncritical items involves cleaning andor low level disinfection

Sanitation bull Process that

reduces microorganisms on an inanimate object to a level below that of infectious hazard (eg dishes and eating utensils are sanitized

Semi critical items bull Devices that come in

contact with no intact skin or mucous membranes but ordinarily do not penetrate them Reprocessing semi critical items involves meticulous cleaning followed preferably by high-level disinfection

Disinfectant effectiveness depends on many factors

bull Type of contaminating microorganism Each disinfectant has unique antimicrobial attributes

bull bull Degree of contamination This determines the quality of disinfectant required and time of exposure

bull bull Amount of proteinaceous material present High protein based materials absorb and neutralize some chemical disinfectants

bull bull Presence of organic matter and other compounds such as soaps may neutralize some disinfectants

bull bull Chemical nature of disinfectant It is important to understand the mode of action in order to select the appropriate disinfectant

Disinfectant effectiveness depends on many factors

bull Concentration and quantity of disinfectant It is important to choose the proper concentration and quantity of disinfectant that is best suited to each situation

bull bull Contact time and temperature Sufficient time and appropriate temperature must be allowed for action of the disinfectant and may depend on the degree of contamination and organic matter load

bull bull Residual activity and effects on fabric and metal should be considered for specific situations

bull bull Application temperature pH and interactions with other compounds must be considered

bull bull Toxicity to the environment and relative safety to people that may be exposed

bullbull Cost An important factor

bull 5

Microbial Characteristics and Microbial Control

Figure 711

PHENOLICS

bull Examples Benzyl-4-chlorophenol Amyl phenol Phenyl phenol

bullAdvantages and disadvantages good general purpose disinfectants not readily inactivated

bullby organic matter active against wide range of organisms (including mycobacterium) but not sporicidal

Phenol as Disinfectant bull Phenolic disinfectants

are effective against bacteria (especially gram positive bacteria) and enveloped viruses They are not effective against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material

Phenol as Disinfectantbull They are not effective

against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material This class of compounds is used for decontamination of the hospital environment including laboratory surfaces and noncritical medical items

Phenol as Disinfectantbull Phenolics are not

recommended for semi critical items because of the lack of validated efficacy data for many of the available formulations and because the residual disinfectant on porous materials may cause tissue irritation even when thoroughly rinsed

Alcohols bull ldquoAlcohol refers to two water-soluble

chemicals ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria (Gram + and Gram -) they also are tuberculocidal fungicidal and virucidal against enveloped viruses Alcohols are not effective against bacterial spores and have limited effectiveness against nonenveloped viruses

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

TerminologybullBiocide or germicide kills microorganisms

bullFungicide kills fungi

bullViricide inactivates viruses

bullBacteriostatic agent stops growth of bacteria

Terminologybull Sepsis bacterial

contamination

bull Asepsis absence of significant contamination

bull Aseptic techniqueminimizes contamination

Antiseptics versus

DisinfectantsAntisepticsUse on skin and mucous membranes to kill

microorganismsNot for use on inanimate objectsDisinfectants

Use to kill microorganisms on inanimate objects

Not for use on skin or mucous membranes

High-level versus low-level disinfectants

Chemical Methodsbull Disinfectants and

antiseptics

bull Surface-active agents (surfactants)

bull Chemical food preservatives

bull Aldehydes

bull Gas sterilization

bull Oxidizing agents

bull [Antibiotics]

Chemicals ndash Disinfection

bull Antiseptics - chemicals that kill microorganisms on living skin or mucous membranes

bull Bactericidal - chemical agents capable of killing bacteria Similarly agents that are virucidal fungicidal or sporicidal are agents capable of killing these organisms

bull Bacteriostatic - Chemical agents that inhibit the growth of bacteria but do not necessarily kill them

Disinfectantsbull Killinhibit growth of

microbes on surfaces

bull Phenols and phenolic damage lipid membranes

bull Active in presence of organic matter

bull Stablebull Persist for long

periods after application

AntisepticsbullBiguanides Chlorhexidine

bullLow toxicitybullUsed on skin and mucous membranes

Cleaning bull Cleaning - the physical removal of foreign material

eg dust soil organic material such as blood secretions excretions and microorganisms Cleaning generally removes rather than kills microorganisms It is accomplished with water detergents and mechanical action The terms ldquodecontaminationrdquo and ldquosanitationrdquo may be used for this process in certain settings eg central service or dietetics Cleaning reduces or eliminates the reservoirs of potential pathogenic organisms

Decontaminationbull Decontamination

the removal of disease-producing microorganisms to leave an item safe for further handling

Disinfectionbull Disinfection the inactivation of disease-

producing microorganisms Disinfection does not destroy bacterial spores Disinfectants are used on inanimate objects in contrast to antiseptics which are used on living tissue Disinfection usually involves chemicals heat or ultraviolet light The nature of chemical disinfection varies with the type of product

High level disinfection bullHigh level disinfection processes

destroy vegetative bacteria mycobacteria fungi and enveloped (lipid) and nonenveloped (non lipid) viruses but not necessarily bacterial spores High level disinfectant chemicals (also called chemical sterilants) must be capable of sterilization when contact time is extended Items must be thoroughly cleaned prior to high level disinfection

Intermediate level disinfection

bull Intermediate level disinfectants kill vegetative bacteria most viruses and most fungi but not resistant bacterial spores

Low level disinfection bullLow level disinfectants kill most vegetative bacteria and some fungi as well as enveloped (lipid) viruses (eg hepatitis B C hantavirus and HIV) Low level disinfectants do not kill mycobacteria or bacterial spores Low level disinfectants are typically used to clean environmental surfaces

AntisepticsbullBiguanides Chlorhexidine

bullLow toxicitybullUsed on skin and mucous membranes

AntisepticsbullAlcohol protein

denaturation and membrane damagebull evaporate quicklybull ethanol and

isopropanolbull [not effective if

taken internally]

Disinfectantsbull Halogens iodine and

chlorinebull Iodine used in

solution Betadineregand Isodinereg

bull Chlorine is a gas that forms bleach (hypochlorite) in water

bull Chloramines are chlorine and ammonia

Selection and Use of Disinfectants

Sterilization ndash An absolute Procedure

bull The destruction of all forms of microbial life including bacteria viruses spores and fungi Items should be cleaned thoroughly before effective sterilization can take place

Noncritical itemsbull That either come in

contact with only intact skin but not mucous membranes or do not directly contact the patient Reprocessing of noncritical items involves cleaning andor low level disinfection

Sanitation bull Process that

reduces microorganisms on an inanimate object to a level below that of infectious hazard (eg dishes and eating utensils are sanitized

Semi critical items bull Devices that come in

contact with no intact skin or mucous membranes but ordinarily do not penetrate them Reprocessing semi critical items involves meticulous cleaning followed preferably by high-level disinfection

Disinfectant effectiveness depends on many factors

bull Type of contaminating microorganism Each disinfectant has unique antimicrobial attributes

bull bull Degree of contamination This determines the quality of disinfectant required and time of exposure

bull bull Amount of proteinaceous material present High protein based materials absorb and neutralize some chemical disinfectants

bull bull Presence of organic matter and other compounds such as soaps may neutralize some disinfectants

bull bull Chemical nature of disinfectant It is important to understand the mode of action in order to select the appropriate disinfectant

Disinfectant effectiveness depends on many factors

bull Concentration and quantity of disinfectant It is important to choose the proper concentration and quantity of disinfectant that is best suited to each situation

bull bull Contact time and temperature Sufficient time and appropriate temperature must be allowed for action of the disinfectant and may depend on the degree of contamination and organic matter load

bull bull Residual activity and effects on fabric and metal should be considered for specific situations

bull bull Application temperature pH and interactions with other compounds must be considered

bull bull Toxicity to the environment and relative safety to people that may be exposed

bullbull Cost An important factor

bull 5

Microbial Characteristics and Microbial Control

Figure 711

PHENOLICS

bull Examples Benzyl-4-chlorophenol Amyl phenol Phenyl phenol

bullAdvantages and disadvantages good general purpose disinfectants not readily inactivated

bullby organic matter active against wide range of organisms (including mycobacterium) but not sporicidal

Phenol as Disinfectant bull Phenolic disinfectants

are effective against bacteria (especially gram positive bacteria) and enveloped viruses They are not effective against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material

Phenol as Disinfectantbull They are not effective

against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material This class of compounds is used for decontamination of the hospital environment including laboratory surfaces and noncritical medical items

Phenol as Disinfectantbull Phenolics are not

recommended for semi critical items because of the lack of validated efficacy data for many of the available formulations and because the residual disinfectant on porous materials may cause tissue irritation even when thoroughly rinsed

Alcohols bull ldquoAlcohol refers to two water-soluble

chemicals ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria (Gram + and Gram -) they also are tuberculocidal fungicidal and virucidal against enveloped viruses Alcohols are not effective against bacterial spores and have limited effectiveness against nonenveloped viruses

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Terminologybull Sepsis bacterial

contamination

bull Asepsis absence of significant contamination

bull Aseptic techniqueminimizes contamination

Antiseptics versus

DisinfectantsAntisepticsUse on skin and mucous membranes to kill

microorganismsNot for use on inanimate objectsDisinfectants

Use to kill microorganisms on inanimate objects

Not for use on skin or mucous membranes

High-level versus low-level disinfectants

Chemical Methodsbull Disinfectants and

antiseptics

bull Surface-active agents (surfactants)

bull Chemical food preservatives

bull Aldehydes

bull Gas sterilization

bull Oxidizing agents

bull [Antibiotics]

Chemicals ndash Disinfection

bull Antiseptics - chemicals that kill microorganisms on living skin or mucous membranes

bull Bactericidal - chemical agents capable of killing bacteria Similarly agents that are virucidal fungicidal or sporicidal are agents capable of killing these organisms

bull Bacteriostatic - Chemical agents that inhibit the growth of bacteria but do not necessarily kill them

Disinfectantsbull Killinhibit growth of

microbes on surfaces

bull Phenols and phenolic damage lipid membranes

bull Active in presence of organic matter

bull Stablebull Persist for long

periods after application

AntisepticsbullBiguanides Chlorhexidine

bullLow toxicitybullUsed on skin and mucous membranes

Cleaning bull Cleaning - the physical removal of foreign material

eg dust soil organic material such as blood secretions excretions and microorganisms Cleaning generally removes rather than kills microorganisms It is accomplished with water detergents and mechanical action The terms ldquodecontaminationrdquo and ldquosanitationrdquo may be used for this process in certain settings eg central service or dietetics Cleaning reduces or eliminates the reservoirs of potential pathogenic organisms

Decontaminationbull Decontamination

the removal of disease-producing microorganisms to leave an item safe for further handling

Disinfectionbull Disinfection the inactivation of disease-

producing microorganisms Disinfection does not destroy bacterial spores Disinfectants are used on inanimate objects in contrast to antiseptics which are used on living tissue Disinfection usually involves chemicals heat or ultraviolet light The nature of chemical disinfection varies with the type of product

High level disinfection bullHigh level disinfection processes

destroy vegetative bacteria mycobacteria fungi and enveloped (lipid) and nonenveloped (non lipid) viruses but not necessarily bacterial spores High level disinfectant chemicals (also called chemical sterilants) must be capable of sterilization when contact time is extended Items must be thoroughly cleaned prior to high level disinfection

Intermediate level disinfection

bull Intermediate level disinfectants kill vegetative bacteria most viruses and most fungi but not resistant bacterial spores

Low level disinfection bullLow level disinfectants kill most vegetative bacteria and some fungi as well as enveloped (lipid) viruses (eg hepatitis B C hantavirus and HIV) Low level disinfectants do not kill mycobacteria or bacterial spores Low level disinfectants are typically used to clean environmental surfaces

AntisepticsbullBiguanides Chlorhexidine

bullLow toxicitybullUsed on skin and mucous membranes

AntisepticsbullAlcohol protein

denaturation and membrane damagebull evaporate quicklybull ethanol and

isopropanolbull [not effective if

taken internally]

Disinfectantsbull Halogens iodine and

chlorinebull Iodine used in

solution Betadineregand Isodinereg

bull Chlorine is a gas that forms bleach (hypochlorite) in water

bull Chloramines are chlorine and ammonia

Selection and Use of Disinfectants

Sterilization ndash An absolute Procedure

bull The destruction of all forms of microbial life including bacteria viruses spores and fungi Items should be cleaned thoroughly before effective sterilization can take place

Noncritical itemsbull That either come in

contact with only intact skin but not mucous membranes or do not directly contact the patient Reprocessing of noncritical items involves cleaning andor low level disinfection

Sanitation bull Process that

reduces microorganisms on an inanimate object to a level below that of infectious hazard (eg dishes and eating utensils are sanitized

Semi critical items bull Devices that come in

contact with no intact skin or mucous membranes but ordinarily do not penetrate them Reprocessing semi critical items involves meticulous cleaning followed preferably by high-level disinfection

Disinfectant effectiveness depends on many factors

bull Type of contaminating microorganism Each disinfectant has unique antimicrobial attributes

bull bull Degree of contamination This determines the quality of disinfectant required and time of exposure

bull bull Amount of proteinaceous material present High protein based materials absorb and neutralize some chemical disinfectants

bull bull Presence of organic matter and other compounds such as soaps may neutralize some disinfectants

bull bull Chemical nature of disinfectant It is important to understand the mode of action in order to select the appropriate disinfectant

Disinfectant effectiveness depends on many factors

bull Concentration and quantity of disinfectant It is important to choose the proper concentration and quantity of disinfectant that is best suited to each situation

bull bull Contact time and temperature Sufficient time and appropriate temperature must be allowed for action of the disinfectant and may depend on the degree of contamination and organic matter load

bull bull Residual activity and effects on fabric and metal should be considered for specific situations

bull bull Application temperature pH and interactions with other compounds must be considered

bull bull Toxicity to the environment and relative safety to people that may be exposed

bullbull Cost An important factor

bull 5

Microbial Characteristics and Microbial Control

Figure 711

PHENOLICS

bull Examples Benzyl-4-chlorophenol Amyl phenol Phenyl phenol

bullAdvantages and disadvantages good general purpose disinfectants not readily inactivated

bullby organic matter active against wide range of organisms (including mycobacterium) but not sporicidal

Phenol as Disinfectant bull Phenolic disinfectants

are effective against bacteria (especially gram positive bacteria) and enveloped viruses They are not effective against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material

Phenol as Disinfectantbull They are not effective

against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material This class of compounds is used for decontamination of the hospital environment including laboratory surfaces and noncritical medical items

Phenol as Disinfectantbull Phenolics are not

recommended for semi critical items because of the lack of validated efficacy data for many of the available formulations and because the residual disinfectant on porous materials may cause tissue irritation even when thoroughly rinsed

Alcohols bull ldquoAlcohol refers to two water-soluble

chemicals ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria (Gram + and Gram -) they also are tuberculocidal fungicidal and virucidal against enveloped viruses Alcohols are not effective against bacterial spores and have limited effectiveness against nonenveloped viruses

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Antiseptics versus

DisinfectantsAntisepticsUse on skin and mucous membranes to kill

microorganismsNot for use on inanimate objectsDisinfectants

Use to kill microorganisms on inanimate objects

Not for use on skin or mucous membranes

High-level versus low-level disinfectants

Chemical Methodsbull Disinfectants and

antiseptics

bull Surface-active agents (surfactants)

bull Chemical food preservatives

bull Aldehydes

bull Gas sterilization

bull Oxidizing agents

bull [Antibiotics]

Chemicals ndash Disinfection

bull Antiseptics - chemicals that kill microorganisms on living skin or mucous membranes

bull Bactericidal - chemical agents capable of killing bacteria Similarly agents that are virucidal fungicidal or sporicidal are agents capable of killing these organisms

bull Bacteriostatic - Chemical agents that inhibit the growth of bacteria but do not necessarily kill them

Disinfectantsbull Killinhibit growth of

microbes on surfaces

bull Phenols and phenolic damage lipid membranes

bull Active in presence of organic matter

bull Stablebull Persist for long

periods after application

AntisepticsbullBiguanides Chlorhexidine

bullLow toxicitybullUsed on skin and mucous membranes

Cleaning bull Cleaning - the physical removal of foreign material

eg dust soil organic material such as blood secretions excretions and microorganisms Cleaning generally removes rather than kills microorganisms It is accomplished with water detergents and mechanical action The terms ldquodecontaminationrdquo and ldquosanitationrdquo may be used for this process in certain settings eg central service or dietetics Cleaning reduces or eliminates the reservoirs of potential pathogenic organisms

Decontaminationbull Decontamination

the removal of disease-producing microorganisms to leave an item safe for further handling

Disinfectionbull Disinfection the inactivation of disease-

producing microorganisms Disinfection does not destroy bacterial spores Disinfectants are used on inanimate objects in contrast to antiseptics which are used on living tissue Disinfection usually involves chemicals heat or ultraviolet light The nature of chemical disinfection varies with the type of product

High level disinfection bullHigh level disinfection processes

destroy vegetative bacteria mycobacteria fungi and enveloped (lipid) and nonenveloped (non lipid) viruses but not necessarily bacterial spores High level disinfectant chemicals (also called chemical sterilants) must be capable of sterilization when contact time is extended Items must be thoroughly cleaned prior to high level disinfection

Intermediate level disinfection

bull Intermediate level disinfectants kill vegetative bacteria most viruses and most fungi but not resistant bacterial spores

Low level disinfection bullLow level disinfectants kill most vegetative bacteria and some fungi as well as enveloped (lipid) viruses (eg hepatitis B C hantavirus and HIV) Low level disinfectants do not kill mycobacteria or bacterial spores Low level disinfectants are typically used to clean environmental surfaces

AntisepticsbullBiguanides Chlorhexidine

bullLow toxicitybullUsed on skin and mucous membranes

AntisepticsbullAlcohol protein

denaturation and membrane damagebull evaporate quicklybull ethanol and

isopropanolbull [not effective if

taken internally]

Disinfectantsbull Halogens iodine and

chlorinebull Iodine used in

solution Betadineregand Isodinereg

bull Chlorine is a gas that forms bleach (hypochlorite) in water

bull Chloramines are chlorine and ammonia

Selection and Use of Disinfectants

Sterilization ndash An absolute Procedure

bull The destruction of all forms of microbial life including bacteria viruses spores and fungi Items should be cleaned thoroughly before effective sterilization can take place

Noncritical itemsbull That either come in

contact with only intact skin but not mucous membranes or do not directly contact the patient Reprocessing of noncritical items involves cleaning andor low level disinfection

Sanitation bull Process that

reduces microorganisms on an inanimate object to a level below that of infectious hazard (eg dishes and eating utensils are sanitized

Semi critical items bull Devices that come in

contact with no intact skin or mucous membranes but ordinarily do not penetrate them Reprocessing semi critical items involves meticulous cleaning followed preferably by high-level disinfection

Disinfectant effectiveness depends on many factors

bull Type of contaminating microorganism Each disinfectant has unique antimicrobial attributes

bull bull Degree of contamination This determines the quality of disinfectant required and time of exposure

bull bull Amount of proteinaceous material present High protein based materials absorb and neutralize some chemical disinfectants

bull bull Presence of organic matter and other compounds such as soaps may neutralize some disinfectants

bull bull Chemical nature of disinfectant It is important to understand the mode of action in order to select the appropriate disinfectant

Disinfectant effectiveness depends on many factors

bull Concentration and quantity of disinfectant It is important to choose the proper concentration and quantity of disinfectant that is best suited to each situation

bull bull Contact time and temperature Sufficient time and appropriate temperature must be allowed for action of the disinfectant and may depend on the degree of contamination and organic matter load

bull bull Residual activity and effects on fabric and metal should be considered for specific situations

bull bull Application temperature pH and interactions with other compounds must be considered

bull bull Toxicity to the environment and relative safety to people that may be exposed

bullbull Cost An important factor

bull 5

Microbial Characteristics and Microbial Control

Figure 711

PHENOLICS

bull Examples Benzyl-4-chlorophenol Amyl phenol Phenyl phenol

bullAdvantages and disadvantages good general purpose disinfectants not readily inactivated

bullby organic matter active against wide range of organisms (including mycobacterium) but not sporicidal

Phenol as Disinfectant bull Phenolic disinfectants

are effective against bacteria (especially gram positive bacteria) and enveloped viruses They are not effective against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material

Phenol as Disinfectantbull They are not effective

against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material This class of compounds is used for decontamination of the hospital environment including laboratory surfaces and noncritical medical items

Phenol as Disinfectantbull Phenolics are not

recommended for semi critical items because of the lack of validated efficacy data for many of the available formulations and because the residual disinfectant on porous materials may cause tissue irritation even when thoroughly rinsed

Alcohols bull ldquoAlcohol refers to two water-soluble

chemicals ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria (Gram + and Gram -) they also are tuberculocidal fungicidal and virucidal against enveloped viruses Alcohols are not effective against bacterial spores and have limited effectiveness against nonenveloped viruses

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Chemical Methodsbull Disinfectants and

antiseptics

bull Surface-active agents (surfactants)

bull Chemical food preservatives

bull Aldehydes

bull Gas sterilization

bull Oxidizing agents

bull [Antibiotics]

Chemicals ndash Disinfection

bull Antiseptics - chemicals that kill microorganisms on living skin or mucous membranes

bull Bactericidal - chemical agents capable of killing bacteria Similarly agents that are virucidal fungicidal or sporicidal are agents capable of killing these organisms

bull Bacteriostatic - Chemical agents that inhibit the growth of bacteria but do not necessarily kill them

Disinfectantsbull Killinhibit growth of

microbes on surfaces

bull Phenols and phenolic damage lipid membranes

bull Active in presence of organic matter

bull Stablebull Persist for long

periods after application

AntisepticsbullBiguanides Chlorhexidine

bullLow toxicitybullUsed on skin and mucous membranes

Cleaning bull Cleaning - the physical removal of foreign material

eg dust soil organic material such as blood secretions excretions and microorganisms Cleaning generally removes rather than kills microorganisms It is accomplished with water detergents and mechanical action The terms ldquodecontaminationrdquo and ldquosanitationrdquo may be used for this process in certain settings eg central service or dietetics Cleaning reduces or eliminates the reservoirs of potential pathogenic organisms

Decontaminationbull Decontamination

the removal of disease-producing microorganisms to leave an item safe for further handling

Disinfectionbull Disinfection the inactivation of disease-

producing microorganisms Disinfection does not destroy bacterial spores Disinfectants are used on inanimate objects in contrast to antiseptics which are used on living tissue Disinfection usually involves chemicals heat or ultraviolet light The nature of chemical disinfection varies with the type of product

High level disinfection bullHigh level disinfection processes

destroy vegetative bacteria mycobacteria fungi and enveloped (lipid) and nonenveloped (non lipid) viruses but not necessarily bacterial spores High level disinfectant chemicals (also called chemical sterilants) must be capable of sterilization when contact time is extended Items must be thoroughly cleaned prior to high level disinfection

Intermediate level disinfection

bull Intermediate level disinfectants kill vegetative bacteria most viruses and most fungi but not resistant bacterial spores

Low level disinfection bullLow level disinfectants kill most vegetative bacteria and some fungi as well as enveloped (lipid) viruses (eg hepatitis B C hantavirus and HIV) Low level disinfectants do not kill mycobacteria or bacterial spores Low level disinfectants are typically used to clean environmental surfaces

AntisepticsbullBiguanides Chlorhexidine

bullLow toxicitybullUsed on skin and mucous membranes

AntisepticsbullAlcohol protein

denaturation and membrane damagebull evaporate quicklybull ethanol and

isopropanolbull [not effective if

taken internally]

Disinfectantsbull Halogens iodine and

chlorinebull Iodine used in

solution Betadineregand Isodinereg

bull Chlorine is a gas that forms bleach (hypochlorite) in water

bull Chloramines are chlorine and ammonia

Selection and Use of Disinfectants

Sterilization ndash An absolute Procedure

bull The destruction of all forms of microbial life including bacteria viruses spores and fungi Items should be cleaned thoroughly before effective sterilization can take place

Noncritical itemsbull That either come in

contact with only intact skin but not mucous membranes or do not directly contact the patient Reprocessing of noncritical items involves cleaning andor low level disinfection

Sanitation bull Process that

reduces microorganisms on an inanimate object to a level below that of infectious hazard (eg dishes and eating utensils are sanitized

Semi critical items bull Devices that come in

contact with no intact skin or mucous membranes but ordinarily do not penetrate them Reprocessing semi critical items involves meticulous cleaning followed preferably by high-level disinfection

Disinfectant effectiveness depends on many factors

bull Type of contaminating microorganism Each disinfectant has unique antimicrobial attributes

bull bull Degree of contamination This determines the quality of disinfectant required and time of exposure

bull bull Amount of proteinaceous material present High protein based materials absorb and neutralize some chemical disinfectants

bull bull Presence of organic matter and other compounds such as soaps may neutralize some disinfectants

bull bull Chemical nature of disinfectant It is important to understand the mode of action in order to select the appropriate disinfectant

Disinfectant effectiveness depends on many factors

bull Concentration and quantity of disinfectant It is important to choose the proper concentration and quantity of disinfectant that is best suited to each situation

bull bull Contact time and temperature Sufficient time and appropriate temperature must be allowed for action of the disinfectant and may depend on the degree of contamination and organic matter load

bull bull Residual activity and effects on fabric and metal should be considered for specific situations

bull bull Application temperature pH and interactions with other compounds must be considered

bull bull Toxicity to the environment and relative safety to people that may be exposed

bullbull Cost An important factor

bull 5

Microbial Characteristics and Microbial Control

Figure 711

PHENOLICS

bull Examples Benzyl-4-chlorophenol Amyl phenol Phenyl phenol

bullAdvantages and disadvantages good general purpose disinfectants not readily inactivated

bullby organic matter active against wide range of organisms (including mycobacterium) but not sporicidal

Phenol as Disinfectant bull Phenolic disinfectants

are effective against bacteria (especially gram positive bacteria) and enveloped viruses They are not effective against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material

Phenol as Disinfectantbull They are not effective

against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material This class of compounds is used for decontamination of the hospital environment including laboratory surfaces and noncritical medical items

Phenol as Disinfectantbull Phenolics are not

recommended for semi critical items because of the lack of validated efficacy data for many of the available formulations and because the residual disinfectant on porous materials may cause tissue irritation even when thoroughly rinsed

Alcohols bull ldquoAlcohol refers to two water-soluble

chemicals ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria (Gram + and Gram -) they also are tuberculocidal fungicidal and virucidal against enveloped viruses Alcohols are not effective against bacterial spores and have limited effectiveness against nonenveloped viruses

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Chemicals ndash Disinfection

bull Antiseptics - chemicals that kill microorganisms on living skin or mucous membranes

bull Bactericidal - chemical agents capable of killing bacteria Similarly agents that are virucidal fungicidal or sporicidal are agents capable of killing these organisms

bull Bacteriostatic - Chemical agents that inhibit the growth of bacteria but do not necessarily kill them

Disinfectantsbull Killinhibit growth of

microbes on surfaces

bull Phenols and phenolic damage lipid membranes

bull Active in presence of organic matter

bull Stablebull Persist for long

periods after application

AntisepticsbullBiguanides Chlorhexidine

bullLow toxicitybullUsed on skin and mucous membranes

Cleaning bull Cleaning - the physical removal of foreign material

eg dust soil organic material such as blood secretions excretions and microorganisms Cleaning generally removes rather than kills microorganisms It is accomplished with water detergents and mechanical action The terms ldquodecontaminationrdquo and ldquosanitationrdquo may be used for this process in certain settings eg central service or dietetics Cleaning reduces or eliminates the reservoirs of potential pathogenic organisms

Decontaminationbull Decontamination

the removal of disease-producing microorganisms to leave an item safe for further handling

Disinfectionbull Disinfection the inactivation of disease-

producing microorganisms Disinfection does not destroy bacterial spores Disinfectants are used on inanimate objects in contrast to antiseptics which are used on living tissue Disinfection usually involves chemicals heat or ultraviolet light The nature of chemical disinfection varies with the type of product

High level disinfection bullHigh level disinfection processes

destroy vegetative bacteria mycobacteria fungi and enveloped (lipid) and nonenveloped (non lipid) viruses but not necessarily bacterial spores High level disinfectant chemicals (also called chemical sterilants) must be capable of sterilization when contact time is extended Items must be thoroughly cleaned prior to high level disinfection

Intermediate level disinfection

bull Intermediate level disinfectants kill vegetative bacteria most viruses and most fungi but not resistant bacterial spores

Low level disinfection bullLow level disinfectants kill most vegetative bacteria and some fungi as well as enveloped (lipid) viruses (eg hepatitis B C hantavirus and HIV) Low level disinfectants do not kill mycobacteria or bacterial spores Low level disinfectants are typically used to clean environmental surfaces

AntisepticsbullBiguanides Chlorhexidine

bullLow toxicitybullUsed on skin and mucous membranes

AntisepticsbullAlcohol protein

denaturation and membrane damagebull evaporate quicklybull ethanol and

isopropanolbull [not effective if

taken internally]

Disinfectantsbull Halogens iodine and

chlorinebull Iodine used in

solution Betadineregand Isodinereg

bull Chlorine is a gas that forms bleach (hypochlorite) in water

bull Chloramines are chlorine and ammonia

Selection and Use of Disinfectants

Sterilization ndash An absolute Procedure

bull The destruction of all forms of microbial life including bacteria viruses spores and fungi Items should be cleaned thoroughly before effective sterilization can take place

Noncritical itemsbull That either come in

contact with only intact skin but not mucous membranes or do not directly contact the patient Reprocessing of noncritical items involves cleaning andor low level disinfection

Sanitation bull Process that

reduces microorganisms on an inanimate object to a level below that of infectious hazard (eg dishes and eating utensils are sanitized

Semi critical items bull Devices that come in

contact with no intact skin or mucous membranes but ordinarily do not penetrate them Reprocessing semi critical items involves meticulous cleaning followed preferably by high-level disinfection

Disinfectant effectiveness depends on many factors

bull Type of contaminating microorganism Each disinfectant has unique antimicrobial attributes

bull bull Degree of contamination This determines the quality of disinfectant required and time of exposure

bull bull Amount of proteinaceous material present High protein based materials absorb and neutralize some chemical disinfectants

bull bull Presence of organic matter and other compounds such as soaps may neutralize some disinfectants

bull bull Chemical nature of disinfectant It is important to understand the mode of action in order to select the appropriate disinfectant

Disinfectant effectiveness depends on many factors

bull Concentration and quantity of disinfectant It is important to choose the proper concentration and quantity of disinfectant that is best suited to each situation

bull bull Contact time and temperature Sufficient time and appropriate temperature must be allowed for action of the disinfectant and may depend on the degree of contamination and organic matter load

bull bull Residual activity and effects on fabric and metal should be considered for specific situations

bull bull Application temperature pH and interactions with other compounds must be considered

bull bull Toxicity to the environment and relative safety to people that may be exposed

bullbull Cost An important factor

bull 5

Microbial Characteristics and Microbial Control

Figure 711

PHENOLICS

bull Examples Benzyl-4-chlorophenol Amyl phenol Phenyl phenol

bullAdvantages and disadvantages good general purpose disinfectants not readily inactivated

bullby organic matter active against wide range of organisms (including mycobacterium) but not sporicidal

Phenol as Disinfectant bull Phenolic disinfectants

are effective against bacteria (especially gram positive bacteria) and enveloped viruses They are not effective against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material

Phenol as Disinfectantbull They are not effective

against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material This class of compounds is used for decontamination of the hospital environment including laboratory surfaces and noncritical medical items

Phenol as Disinfectantbull Phenolics are not

recommended for semi critical items because of the lack of validated efficacy data for many of the available formulations and because the residual disinfectant on porous materials may cause tissue irritation even when thoroughly rinsed

Alcohols bull ldquoAlcohol refers to two water-soluble

chemicals ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria (Gram + and Gram -) they also are tuberculocidal fungicidal and virucidal against enveloped viruses Alcohols are not effective against bacterial spores and have limited effectiveness against nonenveloped viruses

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Disinfectantsbull Killinhibit growth of

microbes on surfaces

bull Phenols and phenolic damage lipid membranes

bull Active in presence of organic matter

bull Stablebull Persist for long

periods after application

AntisepticsbullBiguanides Chlorhexidine

bullLow toxicitybullUsed on skin and mucous membranes

Cleaning bull Cleaning - the physical removal of foreign material

eg dust soil organic material such as blood secretions excretions and microorganisms Cleaning generally removes rather than kills microorganisms It is accomplished with water detergents and mechanical action The terms ldquodecontaminationrdquo and ldquosanitationrdquo may be used for this process in certain settings eg central service or dietetics Cleaning reduces or eliminates the reservoirs of potential pathogenic organisms

Decontaminationbull Decontamination

the removal of disease-producing microorganisms to leave an item safe for further handling

Disinfectionbull Disinfection the inactivation of disease-

producing microorganisms Disinfection does not destroy bacterial spores Disinfectants are used on inanimate objects in contrast to antiseptics which are used on living tissue Disinfection usually involves chemicals heat or ultraviolet light The nature of chemical disinfection varies with the type of product

High level disinfection bullHigh level disinfection processes

destroy vegetative bacteria mycobacteria fungi and enveloped (lipid) and nonenveloped (non lipid) viruses but not necessarily bacterial spores High level disinfectant chemicals (also called chemical sterilants) must be capable of sterilization when contact time is extended Items must be thoroughly cleaned prior to high level disinfection

Intermediate level disinfection

bull Intermediate level disinfectants kill vegetative bacteria most viruses and most fungi but not resistant bacterial spores

Low level disinfection bullLow level disinfectants kill most vegetative bacteria and some fungi as well as enveloped (lipid) viruses (eg hepatitis B C hantavirus and HIV) Low level disinfectants do not kill mycobacteria or bacterial spores Low level disinfectants are typically used to clean environmental surfaces

AntisepticsbullBiguanides Chlorhexidine

bullLow toxicitybullUsed on skin and mucous membranes

AntisepticsbullAlcohol protein

denaturation and membrane damagebull evaporate quicklybull ethanol and

isopropanolbull [not effective if

taken internally]

Disinfectantsbull Halogens iodine and

chlorinebull Iodine used in

solution Betadineregand Isodinereg

bull Chlorine is a gas that forms bleach (hypochlorite) in water

bull Chloramines are chlorine and ammonia

Selection and Use of Disinfectants

Sterilization ndash An absolute Procedure

bull The destruction of all forms of microbial life including bacteria viruses spores and fungi Items should be cleaned thoroughly before effective sterilization can take place

Noncritical itemsbull That either come in

contact with only intact skin but not mucous membranes or do not directly contact the patient Reprocessing of noncritical items involves cleaning andor low level disinfection

Sanitation bull Process that

reduces microorganisms on an inanimate object to a level below that of infectious hazard (eg dishes and eating utensils are sanitized

Semi critical items bull Devices that come in

contact with no intact skin or mucous membranes but ordinarily do not penetrate them Reprocessing semi critical items involves meticulous cleaning followed preferably by high-level disinfection

Disinfectant effectiveness depends on many factors

bull Type of contaminating microorganism Each disinfectant has unique antimicrobial attributes

bull bull Degree of contamination This determines the quality of disinfectant required and time of exposure

bull bull Amount of proteinaceous material present High protein based materials absorb and neutralize some chemical disinfectants

bull bull Presence of organic matter and other compounds such as soaps may neutralize some disinfectants

bull bull Chemical nature of disinfectant It is important to understand the mode of action in order to select the appropriate disinfectant

Disinfectant effectiveness depends on many factors

bull Concentration and quantity of disinfectant It is important to choose the proper concentration and quantity of disinfectant that is best suited to each situation

bull bull Contact time and temperature Sufficient time and appropriate temperature must be allowed for action of the disinfectant and may depend on the degree of contamination and organic matter load

bull bull Residual activity and effects on fabric and metal should be considered for specific situations

bull bull Application temperature pH and interactions with other compounds must be considered

bull bull Toxicity to the environment and relative safety to people that may be exposed

bullbull Cost An important factor

bull 5

Microbial Characteristics and Microbial Control

Figure 711

PHENOLICS

bull Examples Benzyl-4-chlorophenol Amyl phenol Phenyl phenol

bullAdvantages and disadvantages good general purpose disinfectants not readily inactivated

bullby organic matter active against wide range of organisms (including mycobacterium) but not sporicidal

Phenol as Disinfectant bull Phenolic disinfectants

are effective against bacteria (especially gram positive bacteria) and enveloped viruses They are not effective against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material

Phenol as Disinfectantbull They are not effective

against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material This class of compounds is used for decontamination of the hospital environment including laboratory surfaces and noncritical medical items

Phenol as Disinfectantbull Phenolics are not

recommended for semi critical items because of the lack of validated efficacy data for many of the available formulations and because the residual disinfectant on porous materials may cause tissue irritation even when thoroughly rinsed

Alcohols bull ldquoAlcohol refers to two water-soluble

chemicals ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria (Gram + and Gram -) they also are tuberculocidal fungicidal and virucidal against enveloped viruses Alcohols are not effective against bacterial spores and have limited effectiveness against nonenveloped viruses

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

AntisepticsbullBiguanides Chlorhexidine

bullLow toxicitybullUsed on skin and mucous membranes

Cleaning bull Cleaning - the physical removal of foreign material

eg dust soil organic material such as blood secretions excretions and microorganisms Cleaning generally removes rather than kills microorganisms It is accomplished with water detergents and mechanical action The terms ldquodecontaminationrdquo and ldquosanitationrdquo may be used for this process in certain settings eg central service or dietetics Cleaning reduces or eliminates the reservoirs of potential pathogenic organisms

Decontaminationbull Decontamination

the removal of disease-producing microorganisms to leave an item safe for further handling

Disinfectionbull Disinfection the inactivation of disease-

producing microorganisms Disinfection does not destroy bacterial spores Disinfectants are used on inanimate objects in contrast to antiseptics which are used on living tissue Disinfection usually involves chemicals heat or ultraviolet light The nature of chemical disinfection varies with the type of product

High level disinfection bullHigh level disinfection processes

destroy vegetative bacteria mycobacteria fungi and enveloped (lipid) and nonenveloped (non lipid) viruses but not necessarily bacterial spores High level disinfectant chemicals (also called chemical sterilants) must be capable of sterilization when contact time is extended Items must be thoroughly cleaned prior to high level disinfection

Intermediate level disinfection

bull Intermediate level disinfectants kill vegetative bacteria most viruses and most fungi but not resistant bacterial spores

Low level disinfection bullLow level disinfectants kill most vegetative bacteria and some fungi as well as enveloped (lipid) viruses (eg hepatitis B C hantavirus and HIV) Low level disinfectants do not kill mycobacteria or bacterial spores Low level disinfectants are typically used to clean environmental surfaces

AntisepticsbullBiguanides Chlorhexidine

bullLow toxicitybullUsed on skin and mucous membranes

AntisepticsbullAlcohol protein

denaturation and membrane damagebull evaporate quicklybull ethanol and

isopropanolbull [not effective if

taken internally]

Disinfectantsbull Halogens iodine and

chlorinebull Iodine used in

solution Betadineregand Isodinereg

bull Chlorine is a gas that forms bleach (hypochlorite) in water

bull Chloramines are chlorine and ammonia

Selection and Use of Disinfectants

Sterilization ndash An absolute Procedure

bull The destruction of all forms of microbial life including bacteria viruses spores and fungi Items should be cleaned thoroughly before effective sterilization can take place

Noncritical itemsbull That either come in

contact with only intact skin but not mucous membranes or do not directly contact the patient Reprocessing of noncritical items involves cleaning andor low level disinfection

Sanitation bull Process that

reduces microorganisms on an inanimate object to a level below that of infectious hazard (eg dishes and eating utensils are sanitized

Semi critical items bull Devices that come in

contact with no intact skin or mucous membranes but ordinarily do not penetrate them Reprocessing semi critical items involves meticulous cleaning followed preferably by high-level disinfection

Disinfectant effectiveness depends on many factors

bull Type of contaminating microorganism Each disinfectant has unique antimicrobial attributes

bull bull Degree of contamination This determines the quality of disinfectant required and time of exposure

bull bull Amount of proteinaceous material present High protein based materials absorb and neutralize some chemical disinfectants

bull bull Presence of organic matter and other compounds such as soaps may neutralize some disinfectants

bull bull Chemical nature of disinfectant It is important to understand the mode of action in order to select the appropriate disinfectant

Disinfectant effectiveness depends on many factors

bull Concentration and quantity of disinfectant It is important to choose the proper concentration and quantity of disinfectant that is best suited to each situation

bull bull Contact time and temperature Sufficient time and appropriate temperature must be allowed for action of the disinfectant and may depend on the degree of contamination and organic matter load

bull bull Residual activity and effects on fabric and metal should be considered for specific situations

bull bull Application temperature pH and interactions with other compounds must be considered

bull bull Toxicity to the environment and relative safety to people that may be exposed

bullbull Cost An important factor

bull 5

Microbial Characteristics and Microbial Control

Figure 711

PHENOLICS

bull Examples Benzyl-4-chlorophenol Amyl phenol Phenyl phenol

bullAdvantages and disadvantages good general purpose disinfectants not readily inactivated

bullby organic matter active against wide range of organisms (including mycobacterium) but not sporicidal

Phenol as Disinfectant bull Phenolic disinfectants

are effective against bacteria (especially gram positive bacteria) and enveloped viruses They are not effective against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material

Phenol as Disinfectantbull They are not effective

against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material This class of compounds is used for decontamination of the hospital environment including laboratory surfaces and noncritical medical items

Phenol as Disinfectantbull Phenolics are not

recommended for semi critical items because of the lack of validated efficacy data for many of the available formulations and because the residual disinfectant on porous materials may cause tissue irritation even when thoroughly rinsed

Alcohols bull ldquoAlcohol refers to two water-soluble

chemicals ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria (Gram + and Gram -) they also are tuberculocidal fungicidal and virucidal against enveloped viruses Alcohols are not effective against bacterial spores and have limited effectiveness against nonenveloped viruses

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Cleaning bull Cleaning - the physical removal of foreign material

eg dust soil organic material such as blood secretions excretions and microorganisms Cleaning generally removes rather than kills microorganisms It is accomplished with water detergents and mechanical action The terms ldquodecontaminationrdquo and ldquosanitationrdquo may be used for this process in certain settings eg central service or dietetics Cleaning reduces or eliminates the reservoirs of potential pathogenic organisms

Decontaminationbull Decontamination

the removal of disease-producing microorganisms to leave an item safe for further handling

Disinfectionbull Disinfection the inactivation of disease-

producing microorganisms Disinfection does not destroy bacterial spores Disinfectants are used on inanimate objects in contrast to antiseptics which are used on living tissue Disinfection usually involves chemicals heat or ultraviolet light The nature of chemical disinfection varies with the type of product

High level disinfection bullHigh level disinfection processes

destroy vegetative bacteria mycobacteria fungi and enveloped (lipid) and nonenveloped (non lipid) viruses but not necessarily bacterial spores High level disinfectant chemicals (also called chemical sterilants) must be capable of sterilization when contact time is extended Items must be thoroughly cleaned prior to high level disinfection

Intermediate level disinfection

bull Intermediate level disinfectants kill vegetative bacteria most viruses and most fungi but not resistant bacterial spores

Low level disinfection bullLow level disinfectants kill most vegetative bacteria and some fungi as well as enveloped (lipid) viruses (eg hepatitis B C hantavirus and HIV) Low level disinfectants do not kill mycobacteria or bacterial spores Low level disinfectants are typically used to clean environmental surfaces

AntisepticsbullBiguanides Chlorhexidine

bullLow toxicitybullUsed on skin and mucous membranes

AntisepticsbullAlcohol protein

denaturation and membrane damagebull evaporate quicklybull ethanol and

isopropanolbull [not effective if

taken internally]

Disinfectantsbull Halogens iodine and

chlorinebull Iodine used in

solution Betadineregand Isodinereg

bull Chlorine is a gas that forms bleach (hypochlorite) in water

bull Chloramines are chlorine and ammonia

Selection and Use of Disinfectants

Sterilization ndash An absolute Procedure

bull The destruction of all forms of microbial life including bacteria viruses spores and fungi Items should be cleaned thoroughly before effective sterilization can take place

Noncritical itemsbull That either come in

contact with only intact skin but not mucous membranes or do not directly contact the patient Reprocessing of noncritical items involves cleaning andor low level disinfection

Sanitation bull Process that

reduces microorganisms on an inanimate object to a level below that of infectious hazard (eg dishes and eating utensils are sanitized

Semi critical items bull Devices that come in

contact with no intact skin or mucous membranes but ordinarily do not penetrate them Reprocessing semi critical items involves meticulous cleaning followed preferably by high-level disinfection

Disinfectant effectiveness depends on many factors

bull Type of contaminating microorganism Each disinfectant has unique antimicrobial attributes

bull bull Degree of contamination This determines the quality of disinfectant required and time of exposure

bull bull Amount of proteinaceous material present High protein based materials absorb and neutralize some chemical disinfectants

bull bull Presence of organic matter and other compounds such as soaps may neutralize some disinfectants

bull bull Chemical nature of disinfectant It is important to understand the mode of action in order to select the appropriate disinfectant

Disinfectant effectiveness depends on many factors

bull Concentration and quantity of disinfectant It is important to choose the proper concentration and quantity of disinfectant that is best suited to each situation

bull bull Contact time and temperature Sufficient time and appropriate temperature must be allowed for action of the disinfectant and may depend on the degree of contamination and organic matter load

bull bull Residual activity and effects on fabric and metal should be considered for specific situations

bull bull Application temperature pH and interactions with other compounds must be considered

bull bull Toxicity to the environment and relative safety to people that may be exposed

bullbull Cost An important factor

bull 5

Microbial Characteristics and Microbial Control

Figure 711

PHENOLICS

bull Examples Benzyl-4-chlorophenol Amyl phenol Phenyl phenol

bullAdvantages and disadvantages good general purpose disinfectants not readily inactivated

bullby organic matter active against wide range of organisms (including mycobacterium) but not sporicidal

Phenol as Disinfectant bull Phenolic disinfectants

are effective against bacteria (especially gram positive bacteria) and enveloped viruses They are not effective against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material

Phenol as Disinfectantbull They are not effective

against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material This class of compounds is used for decontamination of the hospital environment including laboratory surfaces and noncritical medical items

Phenol as Disinfectantbull Phenolics are not

recommended for semi critical items because of the lack of validated efficacy data for many of the available formulations and because the residual disinfectant on porous materials may cause tissue irritation even when thoroughly rinsed

Alcohols bull ldquoAlcohol refers to two water-soluble

chemicals ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria (Gram + and Gram -) they also are tuberculocidal fungicidal and virucidal against enveloped viruses Alcohols are not effective against bacterial spores and have limited effectiveness against nonenveloped viruses

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Decontaminationbull Decontamination

the removal of disease-producing microorganisms to leave an item safe for further handling

Disinfectionbull Disinfection the inactivation of disease-

producing microorganisms Disinfection does not destroy bacterial spores Disinfectants are used on inanimate objects in contrast to antiseptics which are used on living tissue Disinfection usually involves chemicals heat or ultraviolet light The nature of chemical disinfection varies with the type of product

High level disinfection bullHigh level disinfection processes

destroy vegetative bacteria mycobacteria fungi and enveloped (lipid) and nonenveloped (non lipid) viruses but not necessarily bacterial spores High level disinfectant chemicals (also called chemical sterilants) must be capable of sterilization when contact time is extended Items must be thoroughly cleaned prior to high level disinfection

Intermediate level disinfection

bull Intermediate level disinfectants kill vegetative bacteria most viruses and most fungi but not resistant bacterial spores

Low level disinfection bullLow level disinfectants kill most vegetative bacteria and some fungi as well as enveloped (lipid) viruses (eg hepatitis B C hantavirus and HIV) Low level disinfectants do not kill mycobacteria or bacterial spores Low level disinfectants are typically used to clean environmental surfaces

AntisepticsbullBiguanides Chlorhexidine

bullLow toxicitybullUsed on skin and mucous membranes

AntisepticsbullAlcohol protein

denaturation and membrane damagebull evaporate quicklybull ethanol and

isopropanolbull [not effective if

taken internally]

Disinfectantsbull Halogens iodine and

chlorinebull Iodine used in

solution Betadineregand Isodinereg

bull Chlorine is a gas that forms bleach (hypochlorite) in water

bull Chloramines are chlorine and ammonia

Selection and Use of Disinfectants

Sterilization ndash An absolute Procedure

bull The destruction of all forms of microbial life including bacteria viruses spores and fungi Items should be cleaned thoroughly before effective sterilization can take place

Noncritical itemsbull That either come in

contact with only intact skin but not mucous membranes or do not directly contact the patient Reprocessing of noncritical items involves cleaning andor low level disinfection

Sanitation bull Process that

reduces microorganisms on an inanimate object to a level below that of infectious hazard (eg dishes and eating utensils are sanitized

Semi critical items bull Devices that come in

contact with no intact skin or mucous membranes but ordinarily do not penetrate them Reprocessing semi critical items involves meticulous cleaning followed preferably by high-level disinfection

Disinfectant effectiveness depends on many factors

bull Type of contaminating microorganism Each disinfectant has unique antimicrobial attributes

bull bull Degree of contamination This determines the quality of disinfectant required and time of exposure

bull bull Amount of proteinaceous material present High protein based materials absorb and neutralize some chemical disinfectants

bull bull Presence of organic matter and other compounds such as soaps may neutralize some disinfectants

bull bull Chemical nature of disinfectant It is important to understand the mode of action in order to select the appropriate disinfectant

Disinfectant effectiveness depends on many factors

bull Concentration and quantity of disinfectant It is important to choose the proper concentration and quantity of disinfectant that is best suited to each situation

bull bull Contact time and temperature Sufficient time and appropriate temperature must be allowed for action of the disinfectant and may depend on the degree of contamination and organic matter load

bull bull Residual activity and effects on fabric and metal should be considered for specific situations

bull bull Application temperature pH and interactions with other compounds must be considered

bull bull Toxicity to the environment and relative safety to people that may be exposed

bullbull Cost An important factor

bull 5

Microbial Characteristics and Microbial Control

Figure 711

PHENOLICS

bull Examples Benzyl-4-chlorophenol Amyl phenol Phenyl phenol

bullAdvantages and disadvantages good general purpose disinfectants not readily inactivated

bullby organic matter active against wide range of organisms (including mycobacterium) but not sporicidal

Phenol as Disinfectant bull Phenolic disinfectants

are effective against bacteria (especially gram positive bacteria) and enveloped viruses They are not effective against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material

Phenol as Disinfectantbull They are not effective

against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material This class of compounds is used for decontamination of the hospital environment including laboratory surfaces and noncritical medical items

Phenol as Disinfectantbull Phenolics are not

recommended for semi critical items because of the lack of validated efficacy data for many of the available formulations and because the residual disinfectant on porous materials may cause tissue irritation even when thoroughly rinsed

Alcohols bull ldquoAlcohol refers to two water-soluble

chemicals ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria (Gram + and Gram -) they also are tuberculocidal fungicidal and virucidal against enveloped viruses Alcohols are not effective against bacterial spores and have limited effectiveness against nonenveloped viruses

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Disinfectionbull Disinfection the inactivation of disease-

producing microorganisms Disinfection does not destroy bacterial spores Disinfectants are used on inanimate objects in contrast to antiseptics which are used on living tissue Disinfection usually involves chemicals heat or ultraviolet light The nature of chemical disinfection varies with the type of product

High level disinfection bullHigh level disinfection processes

destroy vegetative bacteria mycobacteria fungi and enveloped (lipid) and nonenveloped (non lipid) viruses but not necessarily bacterial spores High level disinfectant chemicals (also called chemical sterilants) must be capable of sterilization when contact time is extended Items must be thoroughly cleaned prior to high level disinfection

Intermediate level disinfection

bull Intermediate level disinfectants kill vegetative bacteria most viruses and most fungi but not resistant bacterial spores

Low level disinfection bullLow level disinfectants kill most vegetative bacteria and some fungi as well as enveloped (lipid) viruses (eg hepatitis B C hantavirus and HIV) Low level disinfectants do not kill mycobacteria or bacterial spores Low level disinfectants are typically used to clean environmental surfaces

AntisepticsbullBiguanides Chlorhexidine

bullLow toxicitybullUsed on skin and mucous membranes

AntisepticsbullAlcohol protein

denaturation and membrane damagebull evaporate quicklybull ethanol and

isopropanolbull [not effective if

taken internally]

Disinfectantsbull Halogens iodine and

chlorinebull Iodine used in

solution Betadineregand Isodinereg

bull Chlorine is a gas that forms bleach (hypochlorite) in water

bull Chloramines are chlorine and ammonia

Selection and Use of Disinfectants

Sterilization ndash An absolute Procedure

bull The destruction of all forms of microbial life including bacteria viruses spores and fungi Items should be cleaned thoroughly before effective sterilization can take place

Noncritical itemsbull That either come in

contact with only intact skin but not mucous membranes or do not directly contact the patient Reprocessing of noncritical items involves cleaning andor low level disinfection

Sanitation bull Process that

reduces microorganisms on an inanimate object to a level below that of infectious hazard (eg dishes and eating utensils are sanitized

Semi critical items bull Devices that come in

contact with no intact skin or mucous membranes but ordinarily do not penetrate them Reprocessing semi critical items involves meticulous cleaning followed preferably by high-level disinfection

Disinfectant effectiveness depends on many factors

bull Type of contaminating microorganism Each disinfectant has unique antimicrobial attributes

bull bull Degree of contamination This determines the quality of disinfectant required and time of exposure

bull bull Amount of proteinaceous material present High protein based materials absorb and neutralize some chemical disinfectants

bull bull Presence of organic matter and other compounds such as soaps may neutralize some disinfectants

bull bull Chemical nature of disinfectant It is important to understand the mode of action in order to select the appropriate disinfectant

Disinfectant effectiveness depends on many factors

bull Concentration and quantity of disinfectant It is important to choose the proper concentration and quantity of disinfectant that is best suited to each situation

bull bull Contact time and temperature Sufficient time and appropriate temperature must be allowed for action of the disinfectant and may depend on the degree of contamination and organic matter load

bull bull Residual activity and effects on fabric and metal should be considered for specific situations

bull bull Application temperature pH and interactions with other compounds must be considered

bull bull Toxicity to the environment and relative safety to people that may be exposed

bullbull Cost An important factor

bull 5

Microbial Characteristics and Microbial Control

Figure 711

PHENOLICS

bull Examples Benzyl-4-chlorophenol Amyl phenol Phenyl phenol

bullAdvantages and disadvantages good general purpose disinfectants not readily inactivated

bullby organic matter active against wide range of organisms (including mycobacterium) but not sporicidal

Phenol as Disinfectant bull Phenolic disinfectants

are effective against bacteria (especially gram positive bacteria) and enveloped viruses They are not effective against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material

Phenol as Disinfectantbull They are not effective

against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material This class of compounds is used for decontamination of the hospital environment including laboratory surfaces and noncritical medical items

Phenol as Disinfectantbull Phenolics are not

recommended for semi critical items because of the lack of validated efficacy data for many of the available formulations and because the residual disinfectant on porous materials may cause tissue irritation even when thoroughly rinsed

Alcohols bull ldquoAlcohol refers to two water-soluble

chemicals ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria (Gram + and Gram -) they also are tuberculocidal fungicidal and virucidal against enveloped viruses Alcohols are not effective against bacterial spores and have limited effectiveness against nonenveloped viruses

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

High level disinfection bullHigh level disinfection processes

destroy vegetative bacteria mycobacteria fungi and enveloped (lipid) and nonenveloped (non lipid) viruses but not necessarily bacterial spores High level disinfectant chemicals (also called chemical sterilants) must be capable of sterilization when contact time is extended Items must be thoroughly cleaned prior to high level disinfection

Intermediate level disinfection

bull Intermediate level disinfectants kill vegetative bacteria most viruses and most fungi but not resistant bacterial spores

Low level disinfection bullLow level disinfectants kill most vegetative bacteria and some fungi as well as enveloped (lipid) viruses (eg hepatitis B C hantavirus and HIV) Low level disinfectants do not kill mycobacteria or bacterial spores Low level disinfectants are typically used to clean environmental surfaces

AntisepticsbullBiguanides Chlorhexidine

bullLow toxicitybullUsed on skin and mucous membranes

AntisepticsbullAlcohol protein

denaturation and membrane damagebull evaporate quicklybull ethanol and

isopropanolbull [not effective if

taken internally]

Disinfectantsbull Halogens iodine and

chlorinebull Iodine used in

solution Betadineregand Isodinereg

bull Chlorine is a gas that forms bleach (hypochlorite) in water

bull Chloramines are chlorine and ammonia

Selection and Use of Disinfectants

Sterilization ndash An absolute Procedure

bull The destruction of all forms of microbial life including bacteria viruses spores and fungi Items should be cleaned thoroughly before effective sterilization can take place

Noncritical itemsbull That either come in

contact with only intact skin but not mucous membranes or do not directly contact the patient Reprocessing of noncritical items involves cleaning andor low level disinfection

Sanitation bull Process that

reduces microorganisms on an inanimate object to a level below that of infectious hazard (eg dishes and eating utensils are sanitized

Semi critical items bull Devices that come in

contact with no intact skin or mucous membranes but ordinarily do not penetrate them Reprocessing semi critical items involves meticulous cleaning followed preferably by high-level disinfection

Disinfectant effectiveness depends on many factors

bull Type of contaminating microorganism Each disinfectant has unique antimicrobial attributes

bull bull Degree of contamination This determines the quality of disinfectant required and time of exposure

bull bull Amount of proteinaceous material present High protein based materials absorb and neutralize some chemical disinfectants

bull bull Presence of organic matter and other compounds such as soaps may neutralize some disinfectants

bull bull Chemical nature of disinfectant It is important to understand the mode of action in order to select the appropriate disinfectant

Disinfectant effectiveness depends on many factors

bull Concentration and quantity of disinfectant It is important to choose the proper concentration and quantity of disinfectant that is best suited to each situation

bull bull Contact time and temperature Sufficient time and appropriate temperature must be allowed for action of the disinfectant and may depend on the degree of contamination and organic matter load

bull bull Residual activity and effects on fabric and metal should be considered for specific situations

bull bull Application temperature pH and interactions with other compounds must be considered

bull bull Toxicity to the environment and relative safety to people that may be exposed

bullbull Cost An important factor

bull 5

Microbial Characteristics and Microbial Control

Figure 711

PHENOLICS

bull Examples Benzyl-4-chlorophenol Amyl phenol Phenyl phenol

bullAdvantages and disadvantages good general purpose disinfectants not readily inactivated

bullby organic matter active against wide range of organisms (including mycobacterium) but not sporicidal

Phenol as Disinfectant bull Phenolic disinfectants

are effective against bacteria (especially gram positive bacteria) and enveloped viruses They are not effective against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material

Phenol as Disinfectantbull They are not effective

against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material This class of compounds is used for decontamination of the hospital environment including laboratory surfaces and noncritical medical items

Phenol as Disinfectantbull Phenolics are not

recommended for semi critical items because of the lack of validated efficacy data for many of the available formulations and because the residual disinfectant on porous materials may cause tissue irritation even when thoroughly rinsed

Alcohols bull ldquoAlcohol refers to two water-soluble

chemicals ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria (Gram + and Gram -) they also are tuberculocidal fungicidal and virucidal against enveloped viruses Alcohols are not effective against bacterial spores and have limited effectiveness against nonenveloped viruses

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Intermediate level disinfection

bull Intermediate level disinfectants kill vegetative bacteria most viruses and most fungi but not resistant bacterial spores

Low level disinfection bullLow level disinfectants kill most vegetative bacteria and some fungi as well as enveloped (lipid) viruses (eg hepatitis B C hantavirus and HIV) Low level disinfectants do not kill mycobacteria or bacterial spores Low level disinfectants are typically used to clean environmental surfaces

AntisepticsbullBiguanides Chlorhexidine

bullLow toxicitybullUsed on skin and mucous membranes

AntisepticsbullAlcohol protein

denaturation and membrane damagebull evaporate quicklybull ethanol and

isopropanolbull [not effective if

taken internally]

Disinfectantsbull Halogens iodine and

chlorinebull Iodine used in

solution Betadineregand Isodinereg

bull Chlorine is a gas that forms bleach (hypochlorite) in water

bull Chloramines are chlorine and ammonia

Selection and Use of Disinfectants

Sterilization ndash An absolute Procedure

bull The destruction of all forms of microbial life including bacteria viruses spores and fungi Items should be cleaned thoroughly before effective sterilization can take place

Noncritical itemsbull That either come in

contact with only intact skin but not mucous membranes or do not directly contact the patient Reprocessing of noncritical items involves cleaning andor low level disinfection

Sanitation bull Process that

reduces microorganisms on an inanimate object to a level below that of infectious hazard (eg dishes and eating utensils are sanitized

Semi critical items bull Devices that come in

contact with no intact skin or mucous membranes but ordinarily do not penetrate them Reprocessing semi critical items involves meticulous cleaning followed preferably by high-level disinfection

Disinfectant effectiveness depends on many factors

bull Type of contaminating microorganism Each disinfectant has unique antimicrobial attributes

bull bull Degree of contamination This determines the quality of disinfectant required and time of exposure

bull bull Amount of proteinaceous material present High protein based materials absorb and neutralize some chemical disinfectants

bull bull Presence of organic matter and other compounds such as soaps may neutralize some disinfectants

bull bull Chemical nature of disinfectant It is important to understand the mode of action in order to select the appropriate disinfectant

Disinfectant effectiveness depends on many factors

bull Concentration and quantity of disinfectant It is important to choose the proper concentration and quantity of disinfectant that is best suited to each situation

bull bull Contact time and temperature Sufficient time and appropriate temperature must be allowed for action of the disinfectant and may depend on the degree of contamination and organic matter load

bull bull Residual activity and effects on fabric and metal should be considered for specific situations

bull bull Application temperature pH and interactions with other compounds must be considered

bull bull Toxicity to the environment and relative safety to people that may be exposed

bullbull Cost An important factor

bull 5

Microbial Characteristics and Microbial Control

Figure 711

PHENOLICS

bull Examples Benzyl-4-chlorophenol Amyl phenol Phenyl phenol

bullAdvantages and disadvantages good general purpose disinfectants not readily inactivated

bullby organic matter active against wide range of organisms (including mycobacterium) but not sporicidal

Phenol as Disinfectant bull Phenolic disinfectants

are effective against bacteria (especially gram positive bacteria) and enveloped viruses They are not effective against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material

Phenol as Disinfectantbull They are not effective

against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material This class of compounds is used for decontamination of the hospital environment including laboratory surfaces and noncritical medical items

Phenol as Disinfectantbull Phenolics are not

recommended for semi critical items because of the lack of validated efficacy data for many of the available formulations and because the residual disinfectant on porous materials may cause tissue irritation even when thoroughly rinsed

Alcohols bull ldquoAlcohol refers to two water-soluble

chemicals ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria (Gram + and Gram -) they also are tuberculocidal fungicidal and virucidal against enveloped viruses Alcohols are not effective against bacterial spores and have limited effectiveness against nonenveloped viruses

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Low level disinfection bullLow level disinfectants kill most vegetative bacteria and some fungi as well as enveloped (lipid) viruses (eg hepatitis B C hantavirus and HIV) Low level disinfectants do not kill mycobacteria or bacterial spores Low level disinfectants are typically used to clean environmental surfaces

AntisepticsbullBiguanides Chlorhexidine

bullLow toxicitybullUsed on skin and mucous membranes

AntisepticsbullAlcohol protein

denaturation and membrane damagebull evaporate quicklybull ethanol and

isopropanolbull [not effective if

taken internally]

Disinfectantsbull Halogens iodine and

chlorinebull Iodine used in

solution Betadineregand Isodinereg

bull Chlorine is a gas that forms bleach (hypochlorite) in water

bull Chloramines are chlorine and ammonia

Selection and Use of Disinfectants

Sterilization ndash An absolute Procedure

bull The destruction of all forms of microbial life including bacteria viruses spores and fungi Items should be cleaned thoroughly before effective sterilization can take place

Noncritical itemsbull That either come in

contact with only intact skin but not mucous membranes or do not directly contact the patient Reprocessing of noncritical items involves cleaning andor low level disinfection

Sanitation bull Process that

reduces microorganisms on an inanimate object to a level below that of infectious hazard (eg dishes and eating utensils are sanitized

Semi critical items bull Devices that come in

contact with no intact skin or mucous membranes but ordinarily do not penetrate them Reprocessing semi critical items involves meticulous cleaning followed preferably by high-level disinfection

Disinfectant effectiveness depends on many factors

bull Type of contaminating microorganism Each disinfectant has unique antimicrobial attributes

bull bull Degree of contamination This determines the quality of disinfectant required and time of exposure

bull bull Amount of proteinaceous material present High protein based materials absorb and neutralize some chemical disinfectants

bull bull Presence of organic matter and other compounds such as soaps may neutralize some disinfectants

bull bull Chemical nature of disinfectant It is important to understand the mode of action in order to select the appropriate disinfectant

Disinfectant effectiveness depends on many factors

bull Concentration and quantity of disinfectant It is important to choose the proper concentration and quantity of disinfectant that is best suited to each situation

bull bull Contact time and temperature Sufficient time and appropriate temperature must be allowed for action of the disinfectant and may depend on the degree of contamination and organic matter load

bull bull Residual activity and effects on fabric and metal should be considered for specific situations

bull bull Application temperature pH and interactions with other compounds must be considered

bull bull Toxicity to the environment and relative safety to people that may be exposed

bullbull Cost An important factor

bull 5

Microbial Characteristics and Microbial Control

Figure 711

PHENOLICS

bull Examples Benzyl-4-chlorophenol Amyl phenol Phenyl phenol

bullAdvantages and disadvantages good general purpose disinfectants not readily inactivated

bullby organic matter active against wide range of organisms (including mycobacterium) but not sporicidal

Phenol as Disinfectant bull Phenolic disinfectants

are effective against bacteria (especially gram positive bacteria) and enveloped viruses They are not effective against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material

Phenol as Disinfectantbull They are not effective

against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material This class of compounds is used for decontamination of the hospital environment including laboratory surfaces and noncritical medical items

Phenol as Disinfectantbull Phenolics are not

recommended for semi critical items because of the lack of validated efficacy data for many of the available formulations and because the residual disinfectant on porous materials may cause tissue irritation even when thoroughly rinsed

Alcohols bull ldquoAlcohol refers to two water-soluble

chemicals ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria (Gram + and Gram -) they also are tuberculocidal fungicidal and virucidal against enveloped viruses Alcohols are not effective against bacterial spores and have limited effectiveness against nonenveloped viruses

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

AntisepticsbullBiguanides Chlorhexidine

bullLow toxicitybullUsed on skin and mucous membranes

AntisepticsbullAlcohol protein

denaturation and membrane damagebull evaporate quicklybull ethanol and

isopropanolbull [not effective if

taken internally]

Disinfectantsbull Halogens iodine and

chlorinebull Iodine used in

solution Betadineregand Isodinereg

bull Chlorine is a gas that forms bleach (hypochlorite) in water

bull Chloramines are chlorine and ammonia

Selection and Use of Disinfectants

Sterilization ndash An absolute Procedure

bull The destruction of all forms of microbial life including bacteria viruses spores and fungi Items should be cleaned thoroughly before effective sterilization can take place

Noncritical itemsbull That either come in

contact with only intact skin but not mucous membranes or do not directly contact the patient Reprocessing of noncritical items involves cleaning andor low level disinfection

Sanitation bull Process that

reduces microorganisms on an inanimate object to a level below that of infectious hazard (eg dishes and eating utensils are sanitized

Semi critical items bull Devices that come in

contact with no intact skin or mucous membranes but ordinarily do not penetrate them Reprocessing semi critical items involves meticulous cleaning followed preferably by high-level disinfection

Disinfectant effectiveness depends on many factors

bull Type of contaminating microorganism Each disinfectant has unique antimicrobial attributes

bull bull Degree of contamination This determines the quality of disinfectant required and time of exposure

bull bull Amount of proteinaceous material present High protein based materials absorb and neutralize some chemical disinfectants

bull bull Presence of organic matter and other compounds such as soaps may neutralize some disinfectants

bull bull Chemical nature of disinfectant It is important to understand the mode of action in order to select the appropriate disinfectant

Disinfectant effectiveness depends on many factors

bull Concentration and quantity of disinfectant It is important to choose the proper concentration and quantity of disinfectant that is best suited to each situation

bull bull Contact time and temperature Sufficient time and appropriate temperature must be allowed for action of the disinfectant and may depend on the degree of contamination and organic matter load

bull bull Residual activity and effects on fabric and metal should be considered for specific situations

bull bull Application temperature pH and interactions with other compounds must be considered

bull bull Toxicity to the environment and relative safety to people that may be exposed

bullbull Cost An important factor

bull 5

Microbial Characteristics and Microbial Control

Figure 711

PHENOLICS

bull Examples Benzyl-4-chlorophenol Amyl phenol Phenyl phenol

bullAdvantages and disadvantages good general purpose disinfectants not readily inactivated

bullby organic matter active against wide range of organisms (including mycobacterium) but not sporicidal

Phenol as Disinfectant bull Phenolic disinfectants

are effective against bacteria (especially gram positive bacteria) and enveloped viruses They are not effective against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material

Phenol as Disinfectantbull They are not effective

against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material This class of compounds is used for decontamination of the hospital environment including laboratory surfaces and noncritical medical items

Phenol as Disinfectantbull Phenolics are not

recommended for semi critical items because of the lack of validated efficacy data for many of the available formulations and because the residual disinfectant on porous materials may cause tissue irritation even when thoroughly rinsed

Alcohols bull ldquoAlcohol refers to two water-soluble

chemicals ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria (Gram + and Gram -) they also are tuberculocidal fungicidal and virucidal against enveloped viruses Alcohols are not effective against bacterial spores and have limited effectiveness against nonenveloped viruses

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

AntisepticsbullAlcohol protein

denaturation and membrane damagebull evaporate quicklybull ethanol and

isopropanolbull [not effective if

taken internally]

Disinfectantsbull Halogens iodine and

chlorinebull Iodine used in

solution Betadineregand Isodinereg

bull Chlorine is a gas that forms bleach (hypochlorite) in water

bull Chloramines are chlorine and ammonia

Selection and Use of Disinfectants

Sterilization ndash An absolute Procedure

bull The destruction of all forms of microbial life including bacteria viruses spores and fungi Items should be cleaned thoroughly before effective sterilization can take place

Noncritical itemsbull That either come in

contact with only intact skin but not mucous membranes or do not directly contact the patient Reprocessing of noncritical items involves cleaning andor low level disinfection

Sanitation bull Process that

reduces microorganisms on an inanimate object to a level below that of infectious hazard (eg dishes and eating utensils are sanitized

Semi critical items bull Devices that come in

contact with no intact skin or mucous membranes but ordinarily do not penetrate them Reprocessing semi critical items involves meticulous cleaning followed preferably by high-level disinfection

Disinfectant effectiveness depends on many factors

bull Type of contaminating microorganism Each disinfectant has unique antimicrobial attributes

bull bull Degree of contamination This determines the quality of disinfectant required and time of exposure

bull bull Amount of proteinaceous material present High protein based materials absorb and neutralize some chemical disinfectants

bull bull Presence of organic matter and other compounds such as soaps may neutralize some disinfectants

bull bull Chemical nature of disinfectant It is important to understand the mode of action in order to select the appropriate disinfectant

Disinfectant effectiveness depends on many factors

bull Concentration and quantity of disinfectant It is important to choose the proper concentration and quantity of disinfectant that is best suited to each situation

bull bull Contact time and temperature Sufficient time and appropriate temperature must be allowed for action of the disinfectant and may depend on the degree of contamination and organic matter load

bull bull Residual activity and effects on fabric and metal should be considered for specific situations

bull bull Application temperature pH and interactions with other compounds must be considered

bull bull Toxicity to the environment and relative safety to people that may be exposed

bullbull Cost An important factor

bull 5

Microbial Characteristics and Microbial Control

Figure 711

PHENOLICS

bull Examples Benzyl-4-chlorophenol Amyl phenol Phenyl phenol

bullAdvantages and disadvantages good general purpose disinfectants not readily inactivated

bullby organic matter active against wide range of organisms (including mycobacterium) but not sporicidal

Phenol as Disinfectant bull Phenolic disinfectants

are effective against bacteria (especially gram positive bacteria) and enveloped viruses They are not effective against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material

Phenol as Disinfectantbull They are not effective

against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material This class of compounds is used for decontamination of the hospital environment including laboratory surfaces and noncritical medical items

Phenol as Disinfectantbull Phenolics are not

recommended for semi critical items because of the lack of validated efficacy data for many of the available formulations and because the residual disinfectant on porous materials may cause tissue irritation even when thoroughly rinsed

Alcohols bull ldquoAlcohol refers to two water-soluble

chemicals ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria (Gram + and Gram -) they also are tuberculocidal fungicidal and virucidal against enveloped viruses Alcohols are not effective against bacterial spores and have limited effectiveness against nonenveloped viruses

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Disinfectantsbull Halogens iodine and

chlorinebull Iodine used in

solution Betadineregand Isodinereg

bull Chlorine is a gas that forms bleach (hypochlorite) in water

bull Chloramines are chlorine and ammonia

Selection and Use of Disinfectants

Sterilization ndash An absolute Procedure

bull The destruction of all forms of microbial life including bacteria viruses spores and fungi Items should be cleaned thoroughly before effective sterilization can take place

Noncritical itemsbull That either come in

contact with only intact skin but not mucous membranes or do not directly contact the patient Reprocessing of noncritical items involves cleaning andor low level disinfection

Sanitation bull Process that

reduces microorganisms on an inanimate object to a level below that of infectious hazard (eg dishes and eating utensils are sanitized

Semi critical items bull Devices that come in

contact with no intact skin or mucous membranes but ordinarily do not penetrate them Reprocessing semi critical items involves meticulous cleaning followed preferably by high-level disinfection

Disinfectant effectiveness depends on many factors

bull Type of contaminating microorganism Each disinfectant has unique antimicrobial attributes

bull bull Degree of contamination This determines the quality of disinfectant required and time of exposure

bull bull Amount of proteinaceous material present High protein based materials absorb and neutralize some chemical disinfectants

bull bull Presence of organic matter and other compounds such as soaps may neutralize some disinfectants

bull bull Chemical nature of disinfectant It is important to understand the mode of action in order to select the appropriate disinfectant

Disinfectant effectiveness depends on many factors

bull Concentration and quantity of disinfectant It is important to choose the proper concentration and quantity of disinfectant that is best suited to each situation

bull bull Contact time and temperature Sufficient time and appropriate temperature must be allowed for action of the disinfectant and may depend on the degree of contamination and organic matter load

bull bull Residual activity and effects on fabric and metal should be considered for specific situations

bull bull Application temperature pH and interactions with other compounds must be considered

bull bull Toxicity to the environment and relative safety to people that may be exposed

bullbull Cost An important factor

bull 5

Microbial Characteristics and Microbial Control

Figure 711

PHENOLICS

bull Examples Benzyl-4-chlorophenol Amyl phenol Phenyl phenol

bullAdvantages and disadvantages good general purpose disinfectants not readily inactivated

bullby organic matter active against wide range of organisms (including mycobacterium) but not sporicidal

Phenol as Disinfectant bull Phenolic disinfectants

are effective against bacteria (especially gram positive bacteria) and enveloped viruses They are not effective against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material

Phenol as Disinfectantbull They are not effective

against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material This class of compounds is used for decontamination of the hospital environment including laboratory surfaces and noncritical medical items

Phenol as Disinfectantbull Phenolics are not

recommended for semi critical items because of the lack of validated efficacy data for many of the available formulations and because the residual disinfectant on porous materials may cause tissue irritation even when thoroughly rinsed

Alcohols bull ldquoAlcohol refers to two water-soluble

chemicals ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria (Gram + and Gram -) they also are tuberculocidal fungicidal and virucidal against enveloped viruses Alcohols are not effective against bacterial spores and have limited effectiveness against nonenveloped viruses

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Selection and Use of Disinfectants

Sterilization ndash An absolute Procedure

bull The destruction of all forms of microbial life including bacteria viruses spores and fungi Items should be cleaned thoroughly before effective sterilization can take place

Noncritical itemsbull That either come in

contact with only intact skin but not mucous membranes or do not directly contact the patient Reprocessing of noncritical items involves cleaning andor low level disinfection

Sanitation bull Process that

reduces microorganisms on an inanimate object to a level below that of infectious hazard (eg dishes and eating utensils are sanitized

Semi critical items bull Devices that come in

contact with no intact skin or mucous membranes but ordinarily do not penetrate them Reprocessing semi critical items involves meticulous cleaning followed preferably by high-level disinfection

Disinfectant effectiveness depends on many factors

bull Type of contaminating microorganism Each disinfectant has unique antimicrobial attributes

bull bull Degree of contamination This determines the quality of disinfectant required and time of exposure

bull bull Amount of proteinaceous material present High protein based materials absorb and neutralize some chemical disinfectants

bull bull Presence of organic matter and other compounds such as soaps may neutralize some disinfectants

bull bull Chemical nature of disinfectant It is important to understand the mode of action in order to select the appropriate disinfectant

Disinfectant effectiveness depends on many factors

bull Concentration and quantity of disinfectant It is important to choose the proper concentration and quantity of disinfectant that is best suited to each situation

bull bull Contact time and temperature Sufficient time and appropriate temperature must be allowed for action of the disinfectant and may depend on the degree of contamination and organic matter load

bull bull Residual activity and effects on fabric and metal should be considered for specific situations

bull bull Application temperature pH and interactions with other compounds must be considered

bull bull Toxicity to the environment and relative safety to people that may be exposed

bullbull Cost An important factor

bull 5

Microbial Characteristics and Microbial Control

Figure 711

PHENOLICS

bull Examples Benzyl-4-chlorophenol Amyl phenol Phenyl phenol

bullAdvantages and disadvantages good general purpose disinfectants not readily inactivated

bullby organic matter active against wide range of organisms (including mycobacterium) but not sporicidal

Phenol as Disinfectant bull Phenolic disinfectants

are effective against bacteria (especially gram positive bacteria) and enveloped viruses They are not effective against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material

Phenol as Disinfectantbull They are not effective

against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material This class of compounds is used for decontamination of the hospital environment including laboratory surfaces and noncritical medical items

Phenol as Disinfectantbull Phenolics are not

recommended for semi critical items because of the lack of validated efficacy data for many of the available formulations and because the residual disinfectant on porous materials may cause tissue irritation even when thoroughly rinsed

Alcohols bull ldquoAlcohol refers to two water-soluble

chemicals ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria (Gram + and Gram -) they also are tuberculocidal fungicidal and virucidal against enveloped viruses Alcohols are not effective against bacterial spores and have limited effectiveness against nonenveloped viruses

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Sterilization ndash An absolute Procedure

bull The destruction of all forms of microbial life including bacteria viruses spores and fungi Items should be cleaned thoroughly before effective sterilization can take place

Noncritical itemsbull That either come in

contact with only intact skin but not mucous membranes or do not directly contact the patient Reprocessing of noncritical items involves cleaning andor low level disinfection

Sanitation bull Process that

reduces microorganisms on an inanimate object to a level below that of infectious hazard (eg dishes and eating utensils are sanitized

Semi critical items bull Devices that come in

contact with no intact skin or mucous membranes but ordinarily do not penetrate them Reprocessing semi critical items involves meticulous cleaning followed preferably by high-level disinfection

Disinfectant effectiveness depends on many factors

bull Type of contaminating microorganism Each disinfectant has unique antimicrobial attributes

bull bull Degree of contamination This determines the quality of disinfectant required and time of exposure

bull bull Amount of proteinaceous material present High protein based materials absorb and neutralize some chemical disinfectants

bull bull Presence of organic matter and other compounds such as soaps may neutralize some disinfectants

bull bull Chemical nature of disinfectant It is important to understand the mode of action in order to select the appropriate disinfectant

Disinfectant effectiveness depends on many factors

bull Concentration and quantity of disinfectant It is important to choose the proper concentration and quantity of disinfectant that is best suited to each situation

bull bull Contact time and temperature Sufficient time and appropriate temperature must be allowed for action of the disinfectant and may depend on the degree of contamination and organic matter load

bull bull Residual activity and effects on fabric and metal should be considered for specific situations

bull bull Application temperature pH and interactions with other compounds must be considered

bull bull Toxicity to the environment and relative safety to people that may be exposed

bullbull Cost An important factor

bull 5

Microbial Characteristics and Microbial Control

Figure 711

PHENOLICS

bull Examples Benzyl-4-chlorophenol Amyl phenol Phenyl phenol

bullAdvantages and disadvantages good general purpose disinfectants not readily inactivated

bullby organic matter active against wide range of organisms (including mycobacterium) but not sporicidal

Phenol as Disinfectant bull Phenolic disinfectants

are effective against bacteria (especially gram positive bacteria) and enveloped viruses They are not effective against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material

Phenol as Disinfectantbull They are not effective

against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material This class of compounds is used for decontamination of the hospital environment including laboratory surfaces and noncritical medical items

Phenol as Disinfectantbull Phenolics are not

recommended for semi critical items because of the lack of validated efficacy data for many of the available formulations and because the residual disinfectant on porous materials may cause tissue irritation even when thoroughly rinsed

Alcohols bull ldquoAlcohol refers to two water-soluble

chemicals ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria (Gram + and Gram -) they also are tuberculocidal fungicidal and virucidal against enveloped viruses Alcohols are not effective against bacterial spores and have limited effectiveness against nonenveloped viruses

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Noncritical itemsbull That either come in

contact with only intact skin but not mucous membranes or do not directly contact the patient Reprocessing of noncritical items involves cleaning andor low level disinfection

Sanitation bull Process that

reduces microorganisms on an inanimate object to a level below that of infectious hazard (eg dishes and eating utensils are sanitized

Semi critical items bull Devices that come in

contact with no intact skin or mucous membranes but ordinarily do not penetrate them Reprocessing semi critical items involves meticulous cleaning followed preferably by high-level disinfection

Disinfectant effectiveness depends on many factors

bull Type of contaminating microorganism Each disinfectant has unique antimicrobial attributes

bull bull Degree of contamination This determines the quality of disinfectant required and time of exposure

bull bull Amount of proteinaceous material present High protein based materials absorb and neutralize some chemical disinfectants

bull bull Presence of organic matter and other compounds such as soaps may neutralize some disinfectants

bull bull Chemical nature of disinfectant It is important to understand the mode of action in order to select the appropriate disinfectant

Disinfectant effectiveness depends on many factors

bull Concentration and quantity of disinfectant It is important to choose the proper concentration and quantity of disinfectant that is best suited to each situation

bull bull Contact time and temperature Sufficient time and appropriate temperature must be allowed for action of the disinfectant and may depend on the degree of contamination and organic matter load

bull bull Residual activity and effects on fabric and metal should be considered for specific situations

bull bull Application temperature pH and interactions with other compounds must be considered

bull bull Toxicity to the environment and relative safety to people that may be exposed

bullbull Cost An important factor

bull 5

Microbial Characteristics and Microbial Control

Figure 711

PHENOLICS

bull Examples Benzyl-4-chlorophenol Amyl phenol Phenyl phenol

bullAdvantages and disadvantages good general purpose disinfectants not readily inactivated

bullby organic matter active against wide range of organisms (including mycobacterium) but not sporicidal

Phenol as Disinfectant bull Phenolic disinfectants

are effective against bacteria (especially gram positive bacteria) and enveloped viruses They are not effective against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material

Phenol as Disinfectantbull They are not effective

against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material This class of compounds is used for decontamination of the hospital environment including laboratory surfaces and noncritical medical items

Phenol as Disinfectantbull Phenolics are not

recommended for semi critical items because of the lack of validated efficacy data for many of the available formulations and because the residual disinfectant on porous materials may cause tissue irritation even when thoroughly rinsed

Alcohols bull ldquoAlcohol refers to two water-soluble

chemicals ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria (Gram + and Gram -) they also are tuberculocidal fungicidal and virucidal against enveloped viruses Alcohols are not effective against bacterial spores and have limited effectiveness against nonenveloped viruses

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Sanitation bull Process that

reduces microorganisms on an inanimate object to a level below that of infectious hazard (eg dishes and eating utensils are sanitized

Semi critical items bull Devices that come in

contact with no intact skin or mucous membranes but ordinarily do not penetrate them Reprocessing semi critical items involves meticulous cleaning followed preferably by high-level disinfection

Disinfectant effectiveness depends on many factors

bull Type of contaminating microorganism Each disinfectant has unique antimicrobial attributes

bull bull Degree of contamination This determines the quality of disinfectant required and time of exposure

bull bull Amount of proteinaceous material present High protein based materials absorb and neutralize some chemical disinfectants

bull bull Presence of organic matter and other compounds such as soaps may neutralize some disinfectants

bull bull Chemical nature of disinfectant It is important to understand the mode of action in order to select the appropriate disinfectant

Disinfectant effectiveness depends on many factors

bull Concentration and quantity of disinfectant It is important to choose the proper concentration and quantity of disinfectant that is best suited to each situation

bull bull Contact time and temperature Sufficient time and appropriate temperature must be allowed for action of the disinfectant and may depend on the degree of contamination and organic matter load

bull bull Residual activity and effects on fabric and metal should be considered for specific situations

bull bull Application temperature pH and interactions with other compounds must be considered

bull bull Toxicity to the environment and relative safety to people that may be exposed

bullbull Cost An important factor

bull 5

Microbial Characteristics and Microbial Control

Figure 711

PHENOLICS

bull Examples Benzyl-4-chlorophenol Amyl phenol Phenyl phenol

bullAdvantages and disadvantages good general purpose disinfectants not readily inactivated

bullby organic matter active against wide range of organisms (including mycobacterium) but not sporicidal

Phenol as Disinfectant bull Phenolic disinfectants

are effective against bacteria (especially gram positive bacteria) and enveloped viruses They are not effective against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material

Phenol as Disinfectantbull They are not effective

against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material This class of compounds is used for decontamination of the hospital environment including laboratory surfaces and noncritical medical items

Phenol as Disinfectantbull Phenolics are not

recommended for semi critical items because of the lack of validated efficacy data for many of the available formulations and because the residual disinfectant on porous materials may cause tissue irritation even when thoroughly rinsed

Alcohols bull ldquoAlcohol refers to two water-soluble

chemicals ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria (Gram + and Gram -) they also are tuberculocidal fungicidal and virucidal against enveloped viruses Alcohols are not effective against bacterial spores and have limited effectiveness against nonenveloped viruses

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Semi critical items bull Devices that come in

contact with no intact skin or mucous membranes but ordinarily do not penetrate them Reprocessing semi critical items involves meticulous cleaning followed preferably by high-level disinfection

Disinfectant effectiveness depends on many factors

bull Type of contaminating microorganism Each disinfectant has unique antimicrobial attributes

bull bull Degree of contamination This determines the quality of disinfectant required and time of exposure

bull bull Amount of proteinaceous material present High protein based materials absorb and neutralize some chemical disinfectants

bull bull Presence of organic matter and other compounds such as soaps may neutralize some disinfectants

bull bull Chemical nature of disinfectant It is important to understand the mode of action in order to select the appropriate disinfectant

Disinfectant effectiveness depends on many factors

bull Concentration and quantity of disinfectant It is important to choose the proper concentration and quantity of disinfectant that is best suited to each situation

bull bull Contact time and temperature Sufficient time and appropriate temperature must be allowed for action of the disinfectant and may depend on the degree of contamination and organic matter load

bull bull Residual activity and effects on fabric and metal should be considered for specific situations

bull bull Application temperature pH and interactions with other compounds must be considered

bull bull Toxicity to the environment and relative safety to people that may be exposed

bullbull Cost An important factor

bull 5

Microbial Characteristics and Microbial Control

Figure 711

PHENOLICS

bull Examples Benzyl-4-chlorophenol Amyl phenol Phenyl phenol

bullAdvantages and disadvantages good general purpose disinfectants not readily inactivated

bullby organic matter active against wide range of organisms (including mycobacterium) but not sporicidal

Phenol as Disinfectant bull Phenolic disinfectants

are effective against bacteria (especially gram positive bacteria) and enveloped viruses They are not effective against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material

Phenol as Disinfectantbull They are not effective

against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material This class of compounds is used for decontamination of the hospital environment including laboratory surfaces and noncritical medical items

Phenol as Disinfectantbull Phenolics are not

recommended for semi critical items because of the lack of validated efficacy data for many of the available formulations and because the residual disinfectant on porous materials may cause tissue irritation even when thoroughly rinsed

Alcohols bull ldquoAlcohol refers to two water-soluble

chemicals ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria (Gram + and Gram -) they also are tuberculocidal fungicidal and virucidal against enveloped viruses Alcohols are not effective against bacterial spores and have limited effectiveness against nonenveloped viruses

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Disinfectant effectiveness depends on many factors

bull Type of contaminating microorganism Each disinfectant has unique antimicrobial attributes

bull bull Degree of contamination This determines the quality of disinfectant required and time of exposure

bull bull Amount of proteinaceous material present High protein based materials absorb and neutralize some chemical disinfectants

bull bull Presence of organic matter and other compounds such as soaps may neutralize some disinfectants

bull bull Chemical nature of disinfectant It is important to understand the mode of action in order to select the appropriate disinfectant

Disinfectant effectiveness depends on many factors

bull Concentration and quantity of disinfectant It is important to choose the proper concentration and quantity of disinfectant that is best suited to each situation

bull bull Contact time and temperature Sufficient time and appropriate temperature must be allowed for action of the disinfectant and may depend on the degree of contamination and organic matter load

bull bull Residual activity and effects on fabric and metal should be considered for specific situations

bull bull Application temperature pH and interactions with other compounds must be considered

bull bull Toxicity to the environment and relative safety to people that may be exposed

bullbull Cost An important factor

bull 5

Microbial Characteristics and Microbial Control

Figure 711

PHENOLICS

bull Examples Benzyl-4-chlorophenol Amyl phenol Phenyl phenol

bullAdvantages and disadvantages good general purpose disinfectants not readily inactivated

bullby organic matter active against wide range of organisms (including mycobacterium) but not sporicidal

Phenol as Disinfectant bull Phenolic disinfectants

are effective against bacteria (especially gram positive bacteria) and enveloped viruses They are not effective against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material

Phenol as Disinfectantbull They are not effective

against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material This class of compounds is used for decontamination of the hospital environment including laboratory surfaces and noncritical medical items

Phenol as Disinfectantbull Phenolics are not

recommended for semi critical items because of the lack of validated efficacy data for many of the available formulations and because the residual disinfectant on porous materials may cause tissue irritation even when thoroughly rinsed

Alcohols bull ldquoAlcohol refers to two water-soluble

chemicals ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria (Gram + and Gram -) they also are tuberculocidal fungicidal and virucidal against enveloped viruses Alcohols are not effective against bacterial spores and have limited effectiveness against nonenveloped viruses

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Disinfectant effectiveness depends on many factors

bull Concentration and quantity of disinfectant It is important to choose the proper concentration and quantity of disinfectant that is best suited to each situation

bull bull Contact time and temperature Sufficient time and appropriate temperature must be allowed for action of the disinfectant and may depend on the degree of contamination and organic matter load

bull bull Residual activity and effects on fabric and metal should be considered for specific situations

bull bull Application temperature pH and interactions with other compounds must be considered

bull bull Toxicity to the environment and relative safety to people that may be exposed

bullbull Cost An important factor

bull 5

Microbial Characteristics and Microbial Control

Figure 711

PHENOLICS

bull Examples Benzyl-4-chlorophenol Amyl phenol Phenyl phenol

bullAdvantages and disadvantages good general purpose disinfectants not readily inactivated

bullby organic matter active against wide range of organisms (including mycobacterium) but not sporicidal

Phenol as Disinfectant bull Phenolic disinfectants

are effective against bacteria (especially gram positive bacteria) and enveloped viruses They are not effective against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material

Phenol as Disinfectantbull They are not effective

against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material This class of compounds is used for decontamination of the hospital environment including laboratory surfaces and noncritical medical items

Phenol as Disinfectantbull Phenolics are not

recommended for semi critical items because of the lack of validated efficacy data for many of the available formulations and because the residual disinfectant on porous materials may cause tissue irritation even when thoroughly rinsed

Alcohols bull ldquoAlcohol refers to two water-soluble

chemicals ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria (Gram + and Gram -) they also are tuberculocidal fungicidal and virucidal against enveloped viruses Alcohols are not effective against bacterial spores and have limited effectiveness against nonenveloped viruses

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Microbial Characteristics and Microbial Control

Figure 711

PHENOLICS

bull Examples Benzyl-4-chlorophenol Amyl phenol Phenyl phenol

bullAdvantages and disadvantages good general purpose disinfectants not readily inactivated

bullby organic matter active against wide range of organisms (including mycobacterium) but not sporicidal

Phenol as Disinfectant bull Phenolic disinfectants

are effective against bacteria (especially gram positive bacteria) and enveloped viruses They are not effective against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material

Phenol as Disinfectantbull They are not effective

against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material This class of compounds is used for decontamination of the hospital environment including laboratory surfaces and noncritical medical items

Phenol as Disinfectantbull Phenolics are not

recommended for semi critical items because of the lack of validated efficacy data for many of the available formulations and because the residual disinfectant on porous materials may cause tissue irritation even when thoroughly rinsed

Alcohols bull ldquoAlcohol refers to two water-soluble

chemicals ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria (Gram + and Gram -) they also are tuberculocidal fungicidal and virucidal against enveloped viruses Alcohols are not effective against bacterial spores and have limited effectiveness against nonenveloped viruses

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

PHENOLICS

bull Examples Benzyl-4-chlorophenol Amyl phenol Phenyl phenol

bullAdvantages and disadvantages good general purpose disinfectants not readily inactivated

bullby organic matter active against wide range of organisms (including mycobacterium) but not sporicidal

Phenol as Disinfectant bull Phenolic disinfectants

are effective against bacteria (especially gram positive bacteria) and enveloped viruses They are not effective against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material

Phenol as Disinfectantbull They are not effective

against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material This class of compounds is used for decontamination of the hospital environment including laboratory surfaces and noncritical medical items

Phenol as Disinfectantbull Phenolics are not

recommended for semi critical items because of the lack of validated efficacy data for many of the available formulations and because the residual disinfectant on porous materials may cause tissue irritation even when thoroughly rinsed

Alcohols bull ldquoAlcohol refers to two water-soluble

chemicals ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria (Gram + and Gram -) they also are tuberculocidal fungicidal and virucidal against enveloped viruses Alcohols are not effective against bacterial spores and have limited effectiveness against nonenveloped viruses

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Phenol as Disinfectant bull Phenolic disinfectants

are effective against bacteria (especially gram positive bacteria) and enveloped viruses They are not effective against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material

Phenol as Disinfectantbull They are not effective

against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material This class of compounds is used for decontamination of the hospital environment including laboratory surfaces and noncritical medical items

Phenol as Disinfectantbull Phenolics are not

recommended for semi critical items because of the lack of validated efficacy data for many of the available formulations and because the residual disinfectant on porous materials may cause tissue irritation even when thoroughly rinsed

Alcohols bull ldquoAlcohol refers to two water-soluble

chemicals ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria (Gram + and Gram -) they also are tuberculocidal fungicidal and virucidal against enveloped viruses Alcohols are not effective against bacterial spores and have limited effectiveness against nonenveloped viruses

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Phenol as Disinfectantbull They are not effective

against nonenvelopedd viruses and spores These disinfectants maintain their activity in the presence of organic material This class of compounds is used for decontamination of the hospital environment including laboratory surfaces and noncritical medical items

Phenol as Disinfectantbull Phenolics are not

recommended for semi critical items because of the lack of validated efficacy data for many of the available formulations and because the residual disinfectant on porous materials may cause tissue irritation even when thoroughly rinsed

Alcohols bull ldquoAlcohol refers to two water-soluble

chemicals ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria (Gram + and Gram -) they also are tuberculocidal fungicidal and virucidal against enveloped viruses Alcohols are not effective against bacterial spores and have limited effectiveness against nonenveloped viruses

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Phenol as Disinfectantbull Phenolics are not

recommended for semi critical items because of the lack of validated efficacy data for many of the available formulations and because the residual disinfectant on porous materials may cause tissue irritation even when thoroughly rinsed

Alcohols bull ldquoAlcohol refers to two water-soluble

chemicals ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria (Gram + and Gram -) they also are tuberculocidal fungicidal and virucidal against enveloped viruses Alcohols are not effective against bacterial spores and have limited effectiveness against nonenveloped viruses

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Alcohols bull ldquoAlcohol refers to two water-soluble

chemicals ethyl alcohol and isopropyl alcohol These alcohols are rapidly bactericidal rather than bacteriostatic against vegetative forms of bacteria (Gram + and Gram -) they also are tuberculocidal fungicidal and virucidal against enveloped viruses Alcohols are not effective against bacterial spores and have limited effectiveness against nonenveloped viruses

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Alcoholsbull Their cidal activity drops

sharply when diluted below 50 concentration and the optimum bactericidal concentration is in the range of 60-90 solutions in water (volumevolume) The antimicrobial activity of alcohols can be attributed to their ability to denature proteins

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

AlcoholsbullHigher concentrations are less effective as the action of denaturing proteins is inhibited without the presence of water

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Alcoholsbull Alcohols are

commonly used topical antiseptics They are also used to disinfect the surface of medical equipment Alcohols require time to work and they may not penetrate organic material

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Alcoholsbull They also evaporate

rapidly which makes extended exposure time difficult to achieve unless the items are immersed Alcohol irritates tissues They are generally too expensive for general use as a surface disinfectant

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Soap Water and common sense are yet the best antiseptics

William Osler

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Gaining importance in Hand Washing with Alcohols

bull The use of either ethyl alcohol or isopropyl alcohol in a 60-90 solution has recently gained wide acceptance in health care settings as hand antiseptics They can be used as a reasonable substitute for handwashing as long as hands are not visibly soiled

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

HypochloritesbullHypochlorites are the most widely used

of the chlorine disinfectants and are available in a liquid (eg sodium hypochlorite) or solid (eg calcium hypochlorite sodium dichloroisocyanurate) form The most common chlorine products in are aqueous solutions of 4 to 6 sodium hypochlorite which are readily available as ldquohousehold bleachrdquo

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Hypochloritesbull They have a broad

spectrum of antimicrobial activity are unaffected by water hardness are inexpensive and fast acting and have a low incidence of serious toxicity

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Hypochloritesbull Other disadvantages of

hypochlorites include corrosiveness to metals in high concentrations (gt500 ppm) inactivation by organic matter discoloring or ldquobleachingrdquo of fabrics and release of toxic chlorine gas when mixed with ammonia or acid

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Hypochloritesbull Hypochlorites can eliminate both enveloped

and nonenveloped viruses if used in correct dilution and contact time They are also is effective against fungi bacteria and algae but not spores Household bleach is typically diluted using 150 with water (1000ppm) for surface disinfection Bleach solutions have been recommended for use in both hospitals and the community as disinfecting solutions

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Hypochlorites Most recommended in

bullThey are included in most recommendation for decontamination of hepatitis and AIDS viruses

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Hypochloritesbull Hypochlorites are also

the agent of choice in disinfecting surfaces used for food preparation or in bathrooms Organic material such as feces or blood inactivate chlorine based disinfectants therefore surfaces must be clean before their use

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

HypochloritesbullChlorinated

drinking water should not exceed 6 to 10 ppm of free chlorine with the lower value being in continuous flow or low volume reservoir systems

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Iodine And Iodophor Disinfectants

bull These compounds have been incorporated in time release formulations and in soaps (surgical scrubs) Simple iodine tinctures (dissolved in alcohol) have limited cleaning ability These compounds are bactericidal sporicidal virucidal and fungicidal but require a prolonged contact time

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Iodine And Iodophor Disinfectants

bull Besides their use as an antiseptic iodophors have been used for the disinfection of blood culture bottles and medical equipment such as hydrotherapy tanks thermometers and endoscopes

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Iodine And Iodophor Disinfectants

bull The disinfective ability of iodine like chlorine is neutralized in the presence of organic material and hence frequent applications are needed for thorough disinfection Iodine tinctures can be very irritating to tissues can stain fabric and be corrosive

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

HIGH LEVEL DISINFECTANTS

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Hydrogen Peroxidebull Peroxides such as hydrogen peroxide are

often used as antiseptics to clean wounds The activity of peroxides is greatest against anaerobic bacteria Hydrogen peroxide at high concentrations is in some cases is damaging to tissues resulting in a prolonged healing time It is useful for cleaning surgical sites after closure but use sparingly to avoid penetrating suture lines which would inhibit healing

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Hydrogen Peroxidebull Stabilized hydrogen

peroxides can be used to disinfect environmental surfaces The literature contains several accounts of the properties germicidal effectiveness and potential uses for stabilized hydrogen peroxide in the hospital setting

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Hydrogen Peroxidebull Stabilized peroxides

may also be blended with iodophors or quaternary ammonia Hydrogen peroxide is also blended with paracetic acid in high concentrations for use as a high-level disinfectant

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Gluteraldehyde bull Aldehydes have a wide

germicidal spectrum Gluteraldehydes are bactericidal virucidal fungicidal sporicidal and parasiticidal They are used as a disinfectant or sterilant in both liquid and gaseous forms They have moderate residual activity and are effective in the presence of limited amounts of organic material

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Formaldehyde bull Formaldehyde is used as a

disinfectant and sterilant both in the liquid and gaseous states Formaldehyde is sold and used principally as a water-based solution called formalin which is 37 formaldehyde by weight The aqueous solution is bactericidal tuberculocidal fungicidal virucidal and sporicidal

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Formaldehydebull Formaldehydes are very

potent disinfectants which can be highly toxic Use them only as a last resort and then under trained supervision in a well-ventilated setting and with appropriate personal protective equipment

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Formaldehydebull Formaldehyde should be

handled in the workplace as a potential carcinogen with an employee exposure standard that limits an 8 hour time-weighted average exposure to a concentration of 075 ppm For this reason employees should have limited direct contact with formaldehyde and these considerations limit its role in sterilization and disinfection processes

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Ortho-phthalaldehydebull Ortho-phthalaldehyde (OPA) is a chemical sterilant

similar to Gluteraldehydes with similar antimicrobial activity OPA has several potential advantages compared to Gluteraldehydes It has excellent stability over a wide pH range (pH 3-9) is not a known irritant to the eyes and nasal passages does not require exposure monitoring has a barely perceptible odor and requires no activation OPA like Gluteraldehydes has excellent material compatibility

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Ortho-phthalaldehyde

bull A potential disadvantage of OPA is that it stains proteins gray (including unprotected skin) and thus must be handled with caution However skin staining would indicate improper handling that requires additional training andor personal protective equipment (PPE) (gloves eye and mouth protection fluid-resistant gowns)

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Per acetic Acid bullPeracetic or peroxyacetic acid is

characterized by a very rapid action against all microorganisms A special advantage of peracetic acid is it has no harmful decomposition products (ie acetic acid water oxygen hydrogen peroxide) and leaves no residue It remains effective in the presence of organic matter and is sporicidal even at low temperatures

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Per acetic Acidbull It is used in

automated machines to chemically sterilize medical surgical and dental instruments (eg endoscopes arthroscopes)

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Per acetic Acid and Hydrogen Peroxide

bull Two chemical sterilants are available that contain peracetic acid plus hydrogen peroxide (008 peracetic acid plus 10 hydrogen peroxide [no longer marketed] 023 peracetic acid plus 735 hydrogen peroxide) The bactericidal properties of peracetic acid and hydrogen peroxide have been established

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Per acetic acid and hydrogen peroxide useful in Hemodialysis

bull Findings demonstrated that this product inactivated all microorganisms with the exception of bacterial spores within 20 minutes The combination of per acetic acid and hydrogen peroxide has been used for disinfecting hem dialyzers

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Quaternary Ammonium Compounds

bull The quaternaries are good cleaning agents but high water hardness and materials such as cotton and gauze pads may make them less microbiocidal because these materials absorb the active ingredients As with several other disinfectants (eg phenolics iodophors) gram-negative bacteria have been found to survive or grow in these preparations

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Quaternary Ammonium Compounds

bull They are not effective against non-enveloped viruses fungi and bacterial spores QA disinfectants carry a very strong positive charge that makes good contact with negatively charged surfaces This characteristic makes most very good cleaning agents QA compounds are generally low in toxicity but prolonged contact can be irritating The quaternaries are commonly used in ordinary environmental sanitation of noncritical surfaces such as floors furniture and walls

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Work with CautionbullA wide range of microorganisms is

destroyed by varying concentrations of aqueous formaldehyde solutions Although formaldehyde-alcohol is a chemical sterilant and formaldehyde is a high-level disinfectant the hospital uses of formaldehyde are limited by its irritating fumes and the pungent odor that is apparent at very low levels (lt1 ppm)

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Gas plasma Sterilization

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

What is Gas PlasmabullPlasma is a fourth state of matter which

is distinguishable from liquid solid or gas In nature plasma is widespread in outer space

bullGas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particles

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

How Gas Plasma works

bull Many particles are in the form of free radicals

bull A free radical is an Atom with an unpaired electron and is a highly reactive species

bull The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components ie is enzymes and nucleic acids And thereby disrupt the metabolism of microorganisms

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Gas Plasma - Sterilizationbull Plasma sterilization

operates differently because of its specific active agents which are ultraviolet (UV) photons and radicals (atoms or assembly of atoms with unpaired electrons therefore chemically reactive eg O and OH respectively

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

BASIC MECHANISMS OF PLASMA STERILIZATION

bull Destruction by UV irradiation of the genetic material of the microorganism this is a statistical process requiring a sufficient number of lesions of the DNA strands

bull Erosion of the microorganism atom by atom through intrinsic photo desorption

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Advantage of the plasma method

bull An advantage of the plasma method is the possibility under appropriate conditions of achieving such a process at relatively low temperatures (le50 degC) preserving the integrity of polymer-based instruments which cannotbe subjected to autoclaves and ovens Furthermore plasma sterilization is safe both for the operatorand the patient in contrast to EtO

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Hydrogen Peroxide Sterilization Offers Fast Cycle Times

bull Benefits of gas plasma (vaporized hydrogen peroxide) sterilization are fast cycle times the absence of toxic residuals and a low-moisture environment not exceeding 50ordmC a

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

New CDC guidelinesFactors Related To Infection Risk

bull Endoscope contamination accounts for more health care related infections than any other medical instrument and is responsible for consequences ranging from bacterial colonization to death

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Disinfection and sterilization are affected by

bull Initial cleaning of the device

bull Physical complexity of the device

Biofilms and microbial load

bull Microbe type and quantity

bull HLD exposure time and concentration

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

When things go wrong

bullInadequate cleaning

Using the wrong disinfectant

bull Failure to follow procedures

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Guideline ExcerptsInfection Risks

bull ldquoMultiple studies in many countries have documented lack of compliance with established guidelines for disinfection and sterilization

bull Failure to comply with scientifically-based guidelines has led to numerous outbreaks

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Biofilms interfere in effective antimicrobial action

bull ldquoBiofilms are microbial communities that are tightly attached to surfaces and cannot be easily removedBacteria within biofilms are up to 1000 times more resistant to antimicrobials than are the same bacteria in suspension

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Biofilms interfere in effective antimicrobial action

bull ldquoOne multistate investigation found that 239 of the bacterial cultures from the internal channels of 71 gastrointestinal endoscopes grew ge100000 colonies of bacteria after completion of all disinfection and sterilization procedures

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

No Disinfectant is substitute for the following Procedures

bull 1048766 Hand washing (hand hygiene)bull 1048766 The use of personal protective equipment (eg

gloves) when handling blood bodybull substances excretions and secretionsbull 1048766 Appropriate handling of patient care equipment

and soiled linenbull 1048766 The prevention of needle sticksharp injuriesbull 1048766 Environmental cleaningbull 1048766 Appropriate handling of waste andbull 1048766 Taking care of yourself (eg immunization)

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Hand Washing

Yet no substitute for washing hands Do not forget to Wash Your Hands

Immediately on arrival at work

Before and after examining each client

After touching anything that might be contaminated

After handling specimens

Before putting on gloves for clinical procedures

After removing gloves

After using the toilet or latrine

Before leaving work

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Hand Washing is the Best Solution to Prevent the Spread of Infections

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Make your contributions for safe Hospitals

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom

Programme Created by DrTVRao MD for Health

Professionals in Global Health Care

Email

doctortvraogmailcom