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PATHOGENESIS OF BACTERIAL INFECTION AND NOSOCOMIAL INFECTION
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PATHOGENESIS OF BACTERIAL INFECTION AND NOSOCOMIAL
INFECTION
Regi Septian
IntroductionInfection Identification of microorganisms
in host tissue or the blood stream, and an inflammatory response to their presence.
Pathogenesis mechanism of infection and to the mechanism by which disease develops.
Host DefensesHost possesses several layers of endogenous
defense mechanism prevent microbial invasion, limit proliferation of microbes within the host, and contain or eradicate invading microbes.
Skin physical barrier.Mucus + cilia trapping and clearing
respiratory tractGastric acid kills bacteriaMacrophages, complements, immunoglobulin inflammatory response activation
Host DefensesThe magnitude of the response and eventual
outcome generally are related to several factors: (a) the initial number of microbes(b) the rate of microbial proliferation in relation to
containment and killing by host defenses(c) microbial virulence(d) the potency of host defenses. drugs or disease states that diminish any or multiple components of host defenses are associated with higher rates and potentially more grave infections.
EtiologyBacteria, Fungi, Virus
Bacteria:Major etiology of surgical infections.Gram (+) aerobic skin commensals (Staphylococcus
aureus and epidermidis and Streptococcus pyogenes) and enteric organisms such as E. faecalis and faecium
Aerobic skin commensals cause a large percentage of surgical site infections
Enterococci can cause nosocomial infections [urinary tract infections (UTIs) and bacteremia] in immunocompromised or chronically ill patients, but are of relatively low virulence in healthy individuals
BacteriaGram (-) E. coli, Klebsiella pneumoniae,
Serratia marcescens, and Enterobacter, Citrobacter, and Acinetobacter spp.
Anaerobic organism unable to grow or divide poorly in air, as most do not possess the enzyme catalase, which allows for metabolism of reactive oxygen species.
FungiFungi of relevance to surgeons include those
that cause nosocomial infections in surgical patients as part of polymicrobial infections or fungemia (e.g., C. albicans and related species), rare causes of aggressive soft tissue infections (e.g., Mucor, Rhizopus, and Absidia spp.), and so-called opportunistic pathogens that cause infection in the immunocompromised host (e.g., Aspergillus fumigatus, niger, terreus, and other spp., Blastomyces dermatitidis, Coccidioides immitis, and Cryptococcus neoformans).
VirusMost viral infections in surgical patients occur
in the immunocompromised host, particularly those receiving immunosuppression to prevent rejection of a solid organ allograft.
Relevant viruses include adenoviruses, cytomegalovirus, Epstein-Barr virus, herpes simplex virus, and varicella-zoster virus.
Surgeons must be aware of the manifestations of hepatitis B and C virus, as well as HIV infections, including their capacity to be transmitted to health care workers
Nosocomial InfectionInfections that are acquired in hospital (48
hours or more after admission)
SSI (Surgical Site Infection)UTI (Urinary Tract Infection)PneumoniaBacteremia
SSI (Surgical Site Infection)Infections of the tissues, organs, or spaces
exposed by surgeons during performance of an invasive procedure
Classification :Incisional Infections
- Superficial- Deep
Organ/Space infections
Factors related to SSI develoment :The degree of microbial contaminationThe duration of the procedureHost factors (diabetes, malnutrition, obesity,
etc.)
UTI (Urinary Tract Infection)Prolonged use of folley catheter for purpose
of urinary drainageCulture results : > 104 CFU/mL of microbes Postoperative surgical patients should have
urinary catheters removed as quickly as possible, typically within 1 to 2 days, as long as they are mobile.
Hospital Acquired PneumoniaProlonged use of ventilation tubesDiagnosis should be made using the presence
of a purulent sputum, elevated leukocyte count, fever, and new chest x-ray abnormality
Surgical patients should be weaned from mechanical ventilation as soon as feasible, based on oxygenation and inspiratory effort.
BacteremiaProlonged use of venous or arterial accessMany patients who develop intravascular
catheter infections are asymptomatic, often exhibiting an elevation in the blood WBC count.
Routine, scheduled catheter changes are associated with slightly lower rates of infection
4 Important FactorsThe hostThe microbesThe environmentTreatment
The HostPeople in hospital are already sickPoor general resistance to infectionLack of immunity age,
immunocompromisedReduced immunity diabetes, severe burnsPoor local resistance poor blood supply to
tissuesSurgery wound, suturesMedical devices catheters, prostheses,
tubing
The MicrobesNosocomial infections are often caused by
opportunistic pathogens those which do not normally cause infection in healthy people
May be a reflection of reduced defences of host or access to sites not normally colonised by organisms
May be from normal flora or environment
Opportunistic PathogensPseudomonas aeruginosaStaphylococciE. coli and other coliformsStreptococci and EnterococciBacteriodes fragilisCandida albicansHerpes simplex virusCytomegalovirus
The EnvironmentOwn normal flora (endogenous)Infected patientsTraffic of staff and visitorsBlood productsSurgical instruments
Prevention and TreatmentProphylaxis Maneuvers to diminish the
presence of exogenous (surgeon and operating room environment) and endogenous (patient) microbes
General Principles:Minimalize microflora entering the surgical
site:Gloves, gownAseptic and antisepticHair removal before the procedure
Source ControlThe primary precept of surgical infectious disease therapy
consists of drainage of all purulent material, débridement of all infected, devitalized tissue, and debris, and/or removal of foreign bodies at the site of infection, plus remediation of the underlying cause of infection
An ongoing source of contamination (e.g., bowel perforation) or the presence of an aggressive, rapidly-spreading infection (e.g., necrotizing soft tissue infection) invariably requires expedient, aggressive operative intervention, both to remove contaminated material and infected tissue (e.g., radical débridement or amputation) and to remove the initial cause of infection (e.g., bowel resection).
5 Pillars of Infection ControlIsolation and barrier precautionsDecontamination of equipmentPrudent use of antibioticsHand washingDecontamination of environment
Thank You
Harap menambahkan tentang agent infeksi: flora normal, penghasil toksin, etc
Perbedaan kolonisasi dan infeksiInfeksi jamur: dermatophyte? Saprophyte?
Mukor?