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8/13/2019 Midterms - MicroPara
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Microbiology and
Parasitology:Midterm Period
Prepared by:
Lucky P. Roaquin, RN, MAN
STC-CON Faculty
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Learning Objectives
At the end of the course and given simulated/actual
situations/conditions, the student will be able to:
1. Apply the concepts and principles of microbiologyand parasitology in the care of individuals.
2. Utilize principles and techniques in the collection,
handling of specimens and identification of
microorganisms and parasites involved in theinfectious processes.
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Learning Contents
Midterm Period
- Controlling Microbial Growth In Vitro -
- Using Antimicrobial Agents to Control Microbial Growth In Vivo -
- Epidemiology and Public Health -
- Nosocomial Infections & Infection Control -
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Controlling Microbial
GrowthIn Vitro
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Factors that Affects
Bacterial Growth
• Availability of nutrients
• Moisture
•Temperature
• pH
• Osmotic pressure and salinity
• Barometric pressure
• Gaseous atmosphere
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Availability of Nutrients
•
All living organisms require nutrients tosustain life.
• To survive, appropriate nutrients must
be available.• Catabolism and anabolism
• Essential nutrients, elements and trace
elements• About 25 of the 92 naturally occurring
elements are essential to life.
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Moisture
• Water is essential to life.
• Cells consist of 70-95% water.
• Water is required to carry out normalmetabolic processes.
• Endospores and cysts can survive
complete drying process (desiccation).
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Temperature
• Optimum growth temperature
• Minimum growth temperature
• Maximum growth temperature
•
Thermophiles• Mesophiles
• Psychrophiles
– Psychrotrophs- refrigerator temperature 4°C – Psychroduric organism- can endure freezing
temperature
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pH
• Acidity or alkalinity
• Most microorganism prefer a neutral or
slightly alkaline medium (pH 7-7.4)
• Most bacteria grow between pH 6.5 and 7.5
• Molds and yeasts grow between pH 5 and 6
• Acidophi les
• Alkal iphi les
• Vibrio cholerae is the only human pathogenthat grows well above pH 8.
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Osmotic Pressure and Salinity
Osmotic pressu re- pressure that is exerted on a cell
membrane by solutions both inside and outside
the cell.
– Osmosis
• Hypertonic
– Crenation
– Plasmolysis
– Desiccation
• Hypotonic
– Hemolysis
– Plasmoptysis
• Isotonic
– Halophilic and haloduric organisms
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Plasmolysis
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Barometric Pressure
• Most bacteria are not affected by minorchanges in barometric pressure.
• Some thrive at normal atmospheric
pressure (about 14.7 psi).
• Barophi les- thrive deep in the ocean
and in oil wells, where the atmospheric
pressure is high.
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Gaseous Atmosphere
•
Oxygen (O2)
Obligateaerobes
Facultativeanaerobes
Obligateanaerobes
Aerotolerantanaerobes
Microaerophiles
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Encouraging the Growth of
Microorganism In Vitro
• Gather information in the identification ofany pathogens present.
• Learn more about microorganisms.
• Harvest antibiotics and other microbial
products.
• Test new antimicrobial agents and
produce vaccines.
• Viruses, bacteria, fungi and protozoa,
with emphasis on bacteria.
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Culturing Bacteria in the
Laboratory
• petri dishes
• test tubes
• bunsen burners/alcohol lamps
• wire inoculating loops
•
bottles of staining reagents• incubators
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Bacterial Growth
Microbial growth = increase in
number of cells, not cell size
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Generation Time
• The time it takes for one cell to become twocells by binary fission.
– Rapid growers (short GT)
–
Slow growers (long GT)• E. coli, V. cholerae, Staphylococcus and
Streptococcus- 20 mins.
• Pseudomonas and Clostridium- 10 mins.
• M. tuberculosis- 18 to 24 hours
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Culturing Bacteria
• Fast id ious - with complex nutritional
requirements
• Using culture media
• Obligate in tracel lular parasites - do not
grow in culture media
• Treponema pallidum and
Mycobacterium leprae
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Culture Media
• Art i f ic ial media or synthet ic media-
they are prepared in the laboratory
• Culture medium - nutrients prepared for
microbial growth
• Inoculat ion- introduction of microbes
into medium
• Culture- microbes growing in/on culture
medium
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Classification of Culture Media Based on
Whether the Exact Contents are Known
• Chemical ly def ined media- exact
chemical composition is known
• Complex media- exact contents are not
known, from extracts and digests of
yeasts, meat, or plants
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Liquid and Solid Media
•
Liquid media- or broths are containedin tubes, referred to as tubed media.
• Solid media- prepared by adding agar
to liquid media and then poured into testtubes or petri dishes, where the media
solidifies.
– Agar plate
– Agar slant
– Agar but t /deep
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Enriched Medium
• Broth or solid medium containing richsupply of special nutrients that promotes
the growth of fastidious organisms.
• Prepared by adding extra nutrients to amedium called nutrient agar.
• Blood agar and chocolate agar
• N. gonorrhoeae and H. influenzae
S l i M di
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Selective Medium
• Has added inh ib i tors that discourage the
growth of certain organisms without inhibitinggrowth of the organism being sought.
• MacConkey agar- inhibit growth of Gram (+)
bacteria and is selective for Gram (-) bacteria.
• Phenylethyl alcohol agar (PEA) and
col ist in-nal idix ic acid agar (CNA)- inhibit
growth of Gram (-) bacteria.
• Thayer-Mart in agar and Mart in -Lew is agar-selective for N. gonorrhoeae.
• Mannitol salt agar (MSA)- only for salt-
tolerant (haloduric) bacteria
Diff ti l M di
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Differential Medium
• Permits the differentiation of organisms that
grow on the medium.• MacConkey agar- used to differentiate
various Gram (-) bacilli that are isolated from
fecal spcimens.
– Gram (-) bacteria are able to ferment lactose
produces pink colonies, those are unable to
ferment lactose produce colorless colonies.
– Differentiates between LF and NLF Gram (-)
bacteria.
• Mann itol salt agar- used to screen for S.
aureus, pink to yellow.
R b
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Remember…
• Various categories of media are not mutually
exclusive.• Ex: blood agar is enriched and differential
• MacConkey agar and MSA are selective and
differential
• PEA and CNA are enriched and selective
• Thayer-Martin and Martin-Lewis are highly
enriched and highly selective
• Thioglycollate broth (THIO) is a liquid
medium that supports the growth of all
categories of bacteria.
I th hi t
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In the history…
• Robert Koch - described his culture
techniques in 1881.
• Fanny/Frau Hesse- suggested the use of
agar.
• Richard Ju l ius Petr i - invented the glass
Petri dishes.
• Joseph L ister- the first person to obtain a
pre culture of bacterium (Streptococcuslactis) in a liquid medium.
I l i f C l M di
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Inoculation of Culture Media
• Inoculat ion- adding a portion of the
specimen to the medium.
• Inoculaton of a solid or plated medium
involves the use of sterile inoculatingloop to apply a portion of the specimen
to the surface of the medium; a process
commonly referred to as “streaking”.
St ki th A Pl t
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Streaking the Agar Plate
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Importance of Using
“Sterile Technique”
• Necessary to exclude all microorganisms
from a particular area, so that area will be
sterile.
• Media should remain sterile before
inoculation.
• Contaminants- unwanted microorganisms
• Contaminated- if the sample containscontaminants
I b ti
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Incubation
•
After media are inoculated, they must beincubated, and placed in a chamber
(incubator ).
• To culture most human pathogens, the
incubator is set at 35 – 37 o C• Carbon diox ide incubator – 5 to 10%, is
used to isolate capnophiles
•
Non-carbon diox ide incubator –
20 to 21 %of Oxygen
• Anaerobic incubator
B t i l P l ti C t
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Bacterial Population Counts
•
Determine the total number of bacterialcells in the liquid
• Determine the number of viable cells
•Spectrophotometer
• Viab le p late coun t
– Is used to determine the number of viable
bacteria in a liquid sample such as milk,water, ground food diluted in water, or broth
culture.
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Viable Plate Count
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Viable Plate Count
• Number of colonies must be multipliedby the dilution factors.
• If 220 colonies were counted on the
agar plate that had been diluted with a1.0-ml sample of a 1:10,000 dilution,
there were:
• 220 X 10,000= 2,200,000 bacteria/ml
Viable Plate Count
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Viable Plate Count
• Plate Counts: Perform serial dilutions of
a sample
Viable Plate Count
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Viable Plate Count
• Inoculate Petri
plates from
serial dilutions
Viable Plate Count
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Viable Plate Count
• After incubation, count colonies on plates that have
25-250 colonies.
Bacterial Population Growth Curve
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Bacterial Population Growth Curve
• Determined by growing a pure culture of
the organism in a liquid medium at a
constant temperature.
• Data are plotted on a graphic paper,
plotting the logarithm (log10) of the
number of viable bacteria (y-axis)
against the incubation time (x-axis).
Bacteria Population Growth Curve
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Bacteria Population Growth Curve
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Phases of the Growth Curve
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Phases of the Growth Curve
• Lag phase- during which the bacteria absorb
nutrients, synthesize enzymes, and preparefor cell division, the bacteria do not increase in
number.
• Log phase- exponential growth phase;
bacteria multiply so rapidly that the number oforganisms double with each generation time.
• Stat ionary phase- the number of bacteria
that are dividing equals the number that are
dying; greatest population density.
• Death/decl ine phase- culture may die
completely
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Culturing Obligate Intracellular
Pathogens in the Laboratory
Culturing Fungi in the Laboratory
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Culturing Fungi in the Laboratory
• Brain Heart Infu sion Agar
• Sabouraud Dextrose Agar- pH 6.5
selective for fungi
Culturing Protozoa in the
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Culturing Protozoa in the
Laboratory
• Acanthamoeba spp.
• Entamoeba hisolytica
• Balamuthia spp.
•
Giardia lamblia• Leishmania spp.
• Trypanosoma cruzi
• Toxoplasma gondii
• Trichomonas vaginalis• Naegleria fowleri
I hibiti th G th f
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Inhibiting the Growth of
Microorganism In Vitro
• Sterilization
– Dry heat
– Autoclaving (steam under pressure)
– Gas (ex. ethylene glycol)
– Various chemicals (formaldehyde)
– Radiation (UV, gamma rays)
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Disinfection, Pasteurization,
Disinfectants, and Sanitization
• Disinfect ion- removal of pathogens from
nonliving objects by physical or chemical
methods. Ex. Pasteurization
• Disinfectants- are strong chemical
substances that cannot be used on living
tissue.
•Ant iseps is- removal of pathogens from livingtissue
• Sanit izat ion- lower microbial counts on eating
utensils
Microbial Agents
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Microbial Agents
• B ioc idal agents / Germ icidal agents / Microb icidal
agents - are disinfectants that kill microbes• Bacter icidal agents- disinfectants that specifically kill
bacteria but not necessarily bacterial endospores.
• Sporic idal agents - to kill bacterial endospores
• Fungicidal agents- to kill fungi, including fungalspores
• A lgicid al agents - to kill algae in swimming pools and
hot tubs.
• Vir icidal agents - destroy viruses• Pseudomon icidal agents- Pseudomonas species
• Tubercu locidal agents- kill M. tuberculosis
Mi bi t ti A t
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Microbistatic Agents
• Microbistat ic agent- is drug or
chemical that inhibits growth andreproduction of microorganism
• Bacter iostat ic agents- is one that
specifically inhibits the metabolism andreproduction of bacteria.
• Lyophi l izat ion- is a process that
combines dehydration and freezing. – To preserve foods, antibiotics, anti-sera,
microorganisms
Sepsis Asepsis Aseptic Technique
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Sepsis, Asepsis, Aseptic Technique,
Antisepsis, and Antiseptic Technique
• Sepsis- refers to microbial contamination or
presence of pathogens in blood or tissues
• Asepsis- is the absence of significant
contamination.
• Aseptic techniques- prevent microbialcontamination of wounds.
– Hand washing, use of sterile gloves, masks, and
gowns. – Antisepsis : prevention of infection
– Antiseptic Technique- developed by Joseph
Lister, refers to use of antiseptics
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• Alternation of membrane permeability
• Damage to proteins
• Damage to nucleic acids
Actions of Microbial Control Agents
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• Moist heat-
denaturesproteins
• Autoclave:
– Large pressurecooker
– Steam under
pressure – 15 psi, 121.5C,
20 minutes
Using Physical Methods
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• Cold
• Low temperature inhibits microbial
growth
– Refrigeration
– Slow freezing
– Rapid freezing (liquid N)
– Lyophilization (freeze drying)• Desiccat ion
– prevents metabolism
Using Physical Methods
to Inhibit Microbial Growth
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•
Radiat ion- damages DNA – Ionizing radiation (X rays, gamma rays,
electron beams)
– Non-ionizing radiation (UV)
– Ultrasonic waves
– Microwaves kill by heat; not especially
antimicrobial
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• Filtration
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• Gaseous Atmosphere
–
altering the atmosphere in which themicroorganisms are located
– Ex. Gas gangerene
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• Chemical disinfection refers to the use of
chemical agents to inhibit the growth of pathogens,
either temporary or permanent.
Using Chemical Agents
to Inhibit Microbial Growth
Factors to Consider Whenever a
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Factors to Consider Whenever a
Disinfectant is Used
• prior cleaning
• organic load
• bioburden
• contration of disinfectant
• contact time
• physical nature of the object
• temperature and pH
Characteristics of an Ideal
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Characteristics of an Ideal
Microbial Agent
• broad anti-microbial spectrum
• fast acting (short contact time)
• not affected by the presence of organic matter
• non-toxic and non-corrosive
• leave a residual microbial film
• soluble in water and easy to apply
• inexpensive and easy to prepare
• stable, can be stored for long periods
• odorless
How do disinfectant kill
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How do disinfectant kill
microorganisms?
• target and destroy cell membranes
(triclosan, detergents, alcohols,
chlorhexidine and phenolic compounds)
• destroy enzyme and structural enzymes
(hydrogen peroxides, formaldehyde, salt
of heavy metals, formaldehyde and
ethylene oxide)
• attack cell wall or nucleic acids
C
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• Evaluating a disinfectant
– Use-dilution test
1. Metal rings dipped in test bacteria are dried2. Dried cultures placed in disinfectant for 10
min at 20°C
3. Rings transferred to culture media to
determine whether bacteria survivedtreatment
Using Chemical Agents to Inhibit
Microbial Growth
Using Chemical Agents to
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g g
Inhibit Microbial Growth
•
Evaluating a disinfectant• Disk-diffusion method
Chemical Food Preservatives
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Chemical Food Preservatives
•
Chemical Food Preservatives – Organic Acids
• Inhibit metabolism
• Sorbic acid, benzoic acid, calcium propionate
• Control molds and bacteria in foods andcosmetics
• Nitrite prevents endospore germination
•Antibiotics- nisin and natamycinprevent spoilage of cheese
Microbial Characteristics and Microbial Control
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FurtherQuestion/s
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USING ANTIMICROBIAL AGENTS
TO CONTROL MICROBIALGROWTH IN VIVO
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WHAT’S THE WORD?
CHEMOTHERAPY
– Use of drug to treat any disease orcondition
– These “drugs” are called
CHEMOTHERAPUETIC AGENT
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ANTIBIOTICS
– Antimicrobial substance produced by amicroorganism that is effective in killingor inhibiting the growth of othermicroorganisms.
– Semisynthetic antibiotics – chemicallymodified to kill a wider variety ofpathogens or reduce side effects
Ideal Qualities of an Antimicrobial
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Ideal Qualities of an Antimicrobial Agent
Kill or inhibit the growth of pathogens
Cause no damage to the host
Cause no allergic reaction in the host
Stable when stored in solid or liquid form
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Remain in specific tissues in the bodylong enough to be effective
Kill the pathogens before they mutateand become resistant to it.
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Unfortunately…
Most antimicrobials have:
– Some side effects
– Produce allergic reaction – Permit development of mutant strains
Most Common mechanisms of
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Most Common mechanisms of Action of Antimicrobial Agents
Inhibition of cell wall synthesis
Damage to cell membranes
Inhibition of nucleic acid synthesis (DNA or RNA)
Inhibition of protein synthesis
Inhibition of enzyme activity
A tib t i l A t
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Antibacterial Agents(Table 9-1)
Inhibition of cell wall synthesis
– Penicillin interferes with the synthesis and
cross-linking of peptidoglycan in Gram(+) like Staphylococcus andStreptococcus
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JUST ASKING. . .
WHY DOESN’T PENICILLIN ALSO
DESTROY HUMAN CELLS?
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COMPETITIVE INHIBITION
– Sulfonamide molecule is similar in shape to PABA(para-amino benzaldehyde)
– PABA is converted to folic acid which is essentialin the synthesis of some bacterial proteins
– If there is no conversion of PABA to folic acid toessential proteins, the bacterial cell will
eventually die
– Sulfa drugs are BACTERIOSTATIC AGENTS
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JUST ASKING. . .
WILL HUMAN CELLS BE AFFECTED BY
SULFA DRUGS?
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WHAT’S THE WORD?
NARROW - SPECTRUM ANTIBIOTICS
– Destroys only Gram (+) bacteria Vancomycin
– Destroys only Gram (-) bacteria Colistin and Nalidixic acid
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BROAD - SPECTRUM ANTIBIOTICS
– Destructive to both Gram (+) andGram (-) bacteria
Ampicillin
Chloramphenicol
Tetracycline
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SOMETHING TO REMEMBER
Antimicrobial agents work well againstbacterial pathogens because the bacteria(being procaryotic) have different cellularstructures and metabolic pathways that canbe disrupted or destroyed by drugs that donot damage the eucaryotic host’s cell.
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MULTIDRUG THERAPY
Two or ore drugs are used simultaneouslyto kill all the pathogens and to preventresistant mutant strains from emerging.
– Four drugs used in M. tuberculosae infection
Isoniazid
Rifampin Pyrazinamide
Ethambutol or Streptomycin
Synergism VS Antagonism
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Synergism VS Antagonism
SYNERGISM
– Two antimicrobial agents are used totreat an infectious disease a greaterdegree (effect) than that achieved byeither drug alone.
Trimethoprim + Sulfamethoxazole =
Co-trimoxazole (Bactrim and Septra)
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ANTAGONISM
– Two drugs working against each other – The extent of pathogen killing is less than
that achieved by either drug alone.
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ANTIFUNGAL AGENTS
How do they work ?
Binding with cell membrane sterols
– (nystatin, amphotericin B)
Interfere with sterol synthesis – (clotrimazole and miconazole)
Blocks mitosis or nucleic acid synthesis – (griseofulvin and 5-flucytosine)
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ANTIPROTOZOAL AGENTS
How do they work ?
Interfere with DNA and RNA synthesis – (chloroquine, pentamidine,quinacrine)
Interfere with protozoal metabolism – (metronidazole – Flagyl)
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ANTIVIRAL AGENTS
ZIDOVUDINE (AZT)
– First antiviral drug effective against HIV
(1987) – “Coctails” (1990’s) a combination of
antiviral drugs
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SUPERBUGS
Microorganisms that have become
resistant to one or more antimicrobialagents.
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MRSA (Methicillin-resistant S. aureus)
MRSE (Methicillin-resistant S. epidermidis)
VISA (Vancomycin-Intermediate S. aureus)
VRSA (Vancomycin-Resistant S. aureus)-verycommon in nosocomial infection
VRE (Vancomycin – Resistant Enterococcus spp.)
MRTB (Multidrug-Resistant M. tuberculosis)
How can Bacteria Become
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How can Bacteria BecomeResistant to Drugs
INTRINSIC RESISTANCE
– Lack specific target site for the drug(Mycoplama – cellwalless)
– Drug cannot cross the bacterial cell wallor cell membrane
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ACQUIRED RESISTANCE
– Alteration of drug- binding sites due tochromosomal mutation
– Alteration of the structure of the cellmebrane
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– Ability of organism to produce enzymesthat destroys the drug (R-factor is passedon to other bacteria via conjugation)
– Ability to develop Multidrug- Resistancepumps (MDR transporters)-pumps drug
out of the cell before it causes damage
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BETA-LACTAMASES
B-lactam ring – the heart of Penicillinand Cephalosporin structures
If B-lactam is destroyed, the antibioticno longer works
Two types of B-lactamases:
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Two types of B-lactamases:
Penicillinases – destroys the B- lactamrings of Penicillins
Cephalosporinases – destroys the B-lactam ring of Cephalosporins
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Combination of Drugs to Combat theEffect of B-lactamases:
– Clavulinic acid + Amoxicillin = Augmentin
– Clavulinic acid + Tiracarcillin = Timentin
– Sulbactam + Ampicillin = Unasyn – Tazobactam + Piperacillin = Zosyn
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EMPIRIC THERAPY
Clinicians initiate therapy beforelaboratory results are available.
Based on an “educated guess” basedon prior knowledge/ experiences with
the particular type of infectiousdisease the patient has.
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Factors to consider. . .
Laboratory result of pathogen’sidentity – refer to “pocket chart”.
Is patient allergic to anyantimicrobials?
Age of the patient?
Is patient pregnant? In-patient or out-patient?
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Availability of the drug
What is the site of infection?
Medications received by the patient. Other medical problems?
Is patient immunocompromised?
Cost of the drug?
id ff
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Side Effects. . .
Allergies
Toxicity (Chloramphenicol – aplasticanemia)
Superinfection (opportunists and secondaryinvaders overgrowth)
– Antibiotic Associated Diarrhea (AAD) and
Pseudomembranous Colotis (PMC) caused by C.difficile
– Candida albicans infection
Closure / Carry Over
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Closure / Carry Over Activity
What Can Clinicians, ParamedicalProfessionals and Patients Do To Help in theWar Against Drug Resistance? (pp154-155)
– Editorial Cartoon
– Poster
– Slogan
– Jingle – Radio Advertisement
– Poem
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1976
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1976
Legionnaires’ Disease
– severe form of pneumonia, characterizedby headache, chest pain, lung congestion,and high fever. The name is derived froman outbreak at an American Legion
convention in a Philadelphia hotel in July1976.
1992 1993
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1992 - 1993
Escherichia coli O157
– A food-borne disease caused by a particularvariant of the common intestinal bacteriumE. coli . Although E. coli is normally present inthe human intestines, the variant E. coliO157:H7 produces toxins that cause bloodydiarrhea and, in some cases, far more severeproblems, including kidney failure and death. Aperson can become infected by eatingcontaminated meat. Thorough cooking kills thebacteria.
1993
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1993
Hantaviruses are carried by specificrodent hosts and are transmitted directlyfrom host to host by virus-laden saliva,urine, and feces.
Humans are infected through exposure tothe dried excretions from infected rodents.Hantaviruses cause two different human
diseases: hemorrhagic fever with renalsyndrome, in which damage to the kidneysis common, and acute respiratory distresssyndrome, in which damage to the lungs iscommon.
1993
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1993
Cryptosporidiosis
– A diarrheal disease which resulted fromdrinking water that was contaminatedwith Cryptospridium parvum
2002
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2002
West Nile Virus
– infectious organism that can cause fatal
neurological disease in birds, horses, andhumans. The virus is transmitted by the bite ofan infected mosquito. West Nile virus is namedfor a district in Uganda where the virus was firstidentified in humans in 1937.
– As the virus spread, U.S. public health officialsworked with local communities to track thespread of the virus and to control mosquitopopulations to prevent virus transmission.
WHAT’S THE WORD?
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WHAT’S THE WORD?
EPIDEMIOLOGY
– The study of disease, basically thefactors that determine the following:
Frequency
Distribution
Determinants in human population
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Q ti k d b EPIDEMIOLOGISTS
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Questions asked by EPIDEMIOLOGISTS:
What pathogens are causing the infection?
Where do the pathogens come from?
When do certain diseases occur Why do some diseases occur in some places
but not in others
How are pathogens transmitted?
Do some diseases occur only at certain timeof the year? If so, why?
TERMINOLOGIES
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TERMINOLOGIES
COMMUNICABLE DISEASE
– Transmission : person to person
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CONTAGIOUS
– Communicable disease that is easilytransmitted from one person to another
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PANDEMIC DISEASES
– A disease occurring worldwide HIV / AIDS (pp.179 – 180)
Tuberculosis (p. 180)
Malaria (p. 180)
Interactions Among Pathogens, Hosts
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g g ,and the Environment
FACTORS AFFECTING THE OCCURRENCEOF INFECTIOUS DISEASES
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Pertaining to the Pathogen
Virulence Portal of Entry
Number of organisms
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Pertaining to the Host
Health status Nutritional status
Socioeconomic, hygiene,
travel,immune status, substance abuse
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Pertaining to the Environment
Physical factors – Location,
– climate,
– heat,
– cold,
– humidity,
– season of the year
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Availability of appropriate reservoir
Sanitary and housing conditions,adequate waste disposals
Availability of potable water
SIX COMPONENTS IN THE INFECTIOUSDISEASE PROCESS
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DISEASE PROCESS(CHAIN OF INFECTION)
Presence of a pathogen
Source of the pathogen (reservoir)
Portal of exit Mode of transmission
Portal of entry
Susceptible host
FIVE PRINCIPAL MODES OF
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TRANSMISSION
Contact (direct or indirect)
Airborne
Droplet Vehicular
Vectors
Communicable diseases are transmittedfrom person to person in the following
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from person to person in the followingways:
Direct Skin-to-Skin Contact
– Handshake
Direct Mucous membrane –Mucousmembrane Contact
– Kissing – Sexual intercourse
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Indirectly by airborne droplets
– Sneezing
– Coughing
Indirectly by contamination of food
and water by fecal material
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Indirectly by arthropod vectors – Mosquitoes
– Flies
– Fleas
Indirectly by Fomites
– Stethoscope – Gloves
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Indirectly by transfusion of blood orblood products
– Syringes
– Needles
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FurtherQuestion/s
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HEALTHCARE EPIDEMIOLOGY:
NOSOCOMIAL INFECTIONS AND
INFECTION CONTROL
HEALTHCARE EPIDEMIOLOGY
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HEALTHCARE EPIDEMIOLOGY
- “Any activity designed to study and / orimprove patient care outcomes in any typeof healthcare institution or setting.”
- Includes a variety of disciplines andactivities directed at enhancing the qualityof healthcare and preventing and controlling
adverse outcomes.(SHEA)
What is the importance of MICROBIOLOGY toh h l h f i l ?
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the healthcare professionals?
Whether they are working in a hospital,
nursing home, medical or dental clinic,or caring for a sick person they MUST
follow standardized procedures toprevent the spread of communicable
diseases.
TWO TYPES OF INFECTIOUS DISEASES(INFECTIONS)
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(INFECTIONS)
Hospital acquired (Nosocomial)
– Includes those that erupt within 14 daysof hospital discharged
Acquired outside the healthcare
facilities (Community-acquired)
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Iatrogenic Infections
– “physician – induced”
– Result of medical or surgical treatment(surgeons, physicians,healthcarepersonnel)
– Examples: post - surgical woundinfections and urinary tract infections(catheterization)
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Urinary catheters provide a “superhighway” for indigenous normal
flora to access the urinary bladder
70% of nosocomial infections involved
drug – resistant bacteria
HARD TO TREAT NOSOCOMIAL AGENTS
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O OSOCO G S
Pseudomaonas infections
MRTB
VRE
MRSA
MRSE
Others (developed drug-resistant)
– HIV – Candida spp.
– Malarial parasites
MOST COMMON TYPES OF NOSOCOMIALINFECTIONS
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INFECTIONS
1. Urinary Tract Infections
2. Surgical Wound Infections
3. Lower Respiratory Tract Infections4. Bloodstream Infections
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Nosocomial Infection of the GIT iscommonly caused by Clostridium difficile
– Produces enterotoxin and cytotoxin
– AAD (Antibiotic- Associated Diarrhea)-enterotoxin
– PMC (Pseudomembranous Colitis) - cytotoxin
MOST VULNERABLE PATIENTS INHOSPITAL SETTINGS
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HOSPITAL SETTINGS
Elderly patients Women in labor and delivery Premature infants and newborns Surgical and burn patients Diabetic and cancer patients Patients receiving treatment with steroids,
anticancer drugs, anti-lymphocyte serum
and radiation Immunosuppressed patients Patients who are paralyzed and undergoing
renal dialysis or catheterization
MAJOR FACTORS CONTRIBUTING TONOSOCOMIAL INFECTIONS
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NOSOCOMIAL INFECTIONS
Increasing number of drug – resistantpathogens
Failure of personnel to follow infectioncontrol guidelines
Increased number of
immunocompromised patients
OTHER FACTORS
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Indiscriminate use of antimicrobial agents
False sense of security about antimicrobial
agents
Lengthy, more complicated type of surgery
Overcrowding of hospitals, shortages ofstaff
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TWELVE STEPS TO PREVENT
ANTIMICROBIAL RESISTANCE AMONG HOSPITALIZED ADULTS
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WHAT CAN BE DONE TO REDUCE
THE NUMBER OF NOSOCOMIALINFECTIONS?
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WASH HANDS BEFORE YOU . . .
WASH HANDS AFTER YOU. . .
WASH HANDS IN THE FOLLOWINGMANNER. . .
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Roughly 1/3 of adults seem to haveforgotten one of the most basic lessonstheir mothers taught them: wash yourhands properly. Although 95% of people say
that they scrub after using public toilets,researchers from the American Society ofMicrobiology found that only 67 % actuallydo.
PROPER HANDWASHING-It is better tobe safe, than to be sorry.
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TWO TYPES OF ASEPSIS
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MEDICAL ASEPSIS
– “clean technique” involves proceduresand practices that reduce the number andtransmission of pathogens
Hand washing
Personal grooming
Proper cleaning of supplies and equipments
Disinfection
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SURGICAL ASEPSIS
– “sterile technique”
– practices use to keep objects and areassterile
Scrubbing hands and fingernails Sterile gloves , masks, gowns, shoe cover
Using sterile solutions and dressing
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STANDARD PRECAUTIONS
FORINFECTION CONTROL
WORD TO PONDER. . .
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All healthcare workers MUST fullycomprehend the problem of
nosocomial infections, MUST becompletely knowledgeable about
infection control practices, and MUST personally do everything in their
power to prevent nosocomialinfections from occurring.
CARRY – OVER - ACTIVITY
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Interview doctors and paramedicalpractitioners of the effective waysemployed in the hospital to reduce
nosocomial infections.