Nosocomial Infective Organisms

Nosocomial infections are those that occur in a healthcare setting, and are:

• A major contributor of in-patient mortality
• More common in the critically ill
• Caused by a relatively small number of organisms

Epidemiology and Risk Factors

Risk factors include:

• Patient
  • Immunocompromise
    • Critically unwell
    • Comorbid
    • Immunosuppressed
    • Malnutrition
  • Vector of transmission
    • Open wounds
    • Invasive devices
    • Multiple procedures
    • Mechanically ventilated
    • Blood transfusion
  • Length of stay
    • Colonisation with hospital-associated organisms
• Environment
  • Multiple staff
  • Poor aseptic practice
• Organism
  • Resistance
  • Biofilm formation
  • Pathogenicity

Principles

Include:

• Gram positive cocci
  • MRSA
    S. Aureus resistant to most standard anti-Staphylococcal antibiotics, but sensitive to:
    • Glycopeptides
      Vancomycin.
    • Linezolid
      Better pulmonary penetration, may be preferable for MRSA pneumonia.
  • Coagulase-negative Staphylococcus
  • Enterococcus spp.
    • E. Faecalis
    • E. Faecium
• Gram negative bacilli
  • E. Coli
  • P. aeruginosa
  • Klebsiella spp.
  • Serratia marcescens
  • Proteus spp.
  • Acinetobacter baumanni
    Complex and variable resistance pattern.
  • Stenotrophomonas maltophilia
• Fungi
  • Candida spp.

Candidal infections are covered in detail under Candidiasis, and Staphylococcal infections under Staphylococci.

Pseudomonas Aeruginosa

P. Aeruginosa is a:

• Common cause of HAP
• Resistant to common pneumonia therapies
• Commonly colonises the respiratory tract of patients with respiratory disease, leading to recurrent infection
  Including:
  • COPD
  • CF

Stenotrophomonas Maltophilia

Multiresistant environmental organism:

• Intrinsically resistant to carbapenems
  Arises in patients with prolonged carbapenem treatment.
• Generally resistant to β-lactams
• Responsive to cotrimoxazole

Practice

Prevention of Nosocomial Organisms

General	Specific
Handwashing Appropriate infectious precautions MRO surveillance	Oral hygiene Pressure care VAP prevention CLABSI prevention Rationalise antibiotic prescribing Control hyperglycaemia Rationalise immunosuppression Appropriate surgical antimicrobial prophylaxis

Preventative therapies for HAP/VAP and CLABSI are covered under Pneumonia and Central Venous Line, respectively.

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References

1. Bersten, A. D., & Handy, J. M. (2018). Oh’s Intensive Care Manual. Elsevier Gezondheidszorg.