20. Nosocomial infections. Sterilization, disinfection

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Revision as of 14:12, 22 November 2022 by Nikolas (talk | contribs) (Created page with "* Definitions ** Nosocomial disease = disease which is the result of treatment in a hospital ** Nosocomial infection (hospital-acquired infection) = infection which is the result of treatment in a hospital ** Nosocomial epidemic = nosocomial infection that affects two or more patients, and there is a connection between the cases ** Commensal bacteria *** Bacteria which are normally present, but can cause disease in compromised humans * Problems with nosocomial infections...")
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  • Definitions
    • Nosocomial disease = disease which is the result of treatment in a hospital
    • Nosocomial infection (hospital-acquired infection) = infection which is the result of treatment in a hospital
    • Nosocomial epidemic = nosocomial infection that affects two or more patients, and there is a connection between the cases
    • Commensal bacteria
      • Bacteria which are normally present, but can cause disease in compromised humans
  • Problems with nosocomial infections
    • Many people in small area
    • Hospitalized people often have impaired immunity or condition
    • Microorganisms in the hospital often have increased resistance to antibiotics
    • Microorganisms in the hospital are often more virulent than microorganisms in the community
  • The primary factors of epidemic process for nosocomial infections
    • Source of nosocomial infection
      • The patients themselves
        • From commensal bacteria
      • Other patients
      • Staff
      • Visitors
      • Medical equipment
      • Bedsheets
    • Route of transmission
      • Direct contact
      • Indirect
        • Airborne
        • Waterborne
        • Foodborne
        • Objects, instruments
          • Clothing
          • Bedsheets
    • Susceptible population
      • High number of susceptible people
      • Infants
      • Elderly
      • Immunocompromised
        • Diabetes
        • Cancer
        • Polytrauma
        • Surgical patients
    • Secondary factors
      • Crowded rooms
      • Insufficient number of cleaning and nursing staff
      • Lack of medical staff’s preventive approach
  • Pathogens
    • Bacteria
      • Staph. saprophyticus, Staph. epidermidis
      • E. coli
        • A commensal bacterium
        • May colonize surgical sites, needles, catheters
        • Can be highly antibiotic resistant
      • Clostridium
        • Causes gangrene
      • Staph. aureus, MRSA
        • A commensal bacterium
      • Pseudomonas
        • Likes wet and damp areas
    • Viruses
      • Hepatitis B, C
        • Transfusions, dialysis, injections, endoscopy
      • RSV, rotavirus, enterovirus
        • Faecal-oral or hand-to-mouth
    • Parasites
      • Giardia lamblia
      • Scabies
    • Fungi
      • Often cause infections in immunosuppressed patients
      • Candida albicans
      • Aspergillus
      • Cryptococcus
      • Cryptosporidium
  • Diseases
    • Pneumonia
      • 15% of nosocomial diseases
      • 57% mortality
      • S. aureus
      • Pseudomonas
      • Klebsiella
      • Risk
        • Intubation
        • Artificial ventilation
    • UTI
      • 35% of nosocomial diseases
      • 0,1% mortality
      • E. coli (endogenous)
      • Risk: Catheter
    • Surgical site infections
      • S. aureus
      • E. coli
    • Sepsis
      • 23% mortality
      • Risk: Infusion/injection
  • Most commonly affected wards
    • Surgery
    • ICU
    • Paediatrics
  • Respiratory tract infections and sepsis are the most common cause of mortality in hospitals
  • Catheters, surgical wounds, intubation, artificial ventilation are common foci where infection can originate

Preventing nosocomial infections

  • Risk stratification
  • Reducing person-to-person transmission
    • Disinfection of hands
      • Before, during and after patient contact
      • Disinfection = reduce the number of microorganisms, killing most harmful microorganisms
      • Sterilization = kill all microorganisms
    • Personal hygiene
    • Protective equipment
  • Preventing transmission from the environment
    • Asepsis, antisepsis, isolation of patients
    • Sterilization of equipment
    • Limit overuse of antibiotics
  • Education and training of medical staff

Multi-resistant bacteria

  • MRSA
    • Infects skin, wounds, urinary tract, respiratory tract
  • ESBL – extended spectrum beta lactamase
    • Resistant to cephalosporins, penicillins and aztreonam
    • Treatment: carbapenems
    • Often in E. coli or Klebsiella pneumoniae

For this topic you should also known sterilisation and disinfection in detail (everything from them documenting every step (in case of infection, or a potential lawsuit) what type of methods, phenol-coefficient, Joseph Lister, what kind of methods you would use to sterilize fluids to before you administer it (autoclave), biological indicators, etc. Microbiology 1 covered this.