Nosocomial Infections

Nosocomial Infections - Hospital Gremlins 101

• Nosocomial infections (Hospital-Acquired Infections, HAIs): Acquired ≥48 hrs post-admission, not incubating at admission.
• Common Types:
  • Catheter-Associated UTI (CAUTI)
  • Central Line-Associated Bloodstream Infection (CLABSI)
  • Hospital-Acquired/Ventilator-Associated Pneumonia (HAP/VAP)
  • Surgical Site Infection (SSI)
  • Clostridioides difficile Infection (CDI)
• Key Pathogens:
  • 📌 ESCAPE: Enterococcus faecium, Staphylococcus aureus, Clostridium difficile, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacteriaceae
  • MRSA (Methicillin-Resistant S. aureus)
  • VRE (Vancomycin-Resistant Enterococci)
• Risk Factors: Prolonged hospitalization, invasive devices (catheters, ventilators), immunosuppression, elderly, recent surgery/antibiotics.

⭐ Most common HAI is CAUTI. VAP (Ventilator-Associated Pneumonia) has the highest mortality among HAIs.

Device Drama - Tubes & Trouble

• CAUTI (Catheter-Associated UTI): UTI with indwelling urinary catheter (IUC) ≥2 days.

  • Pathogens: E. coli, Klebsiella, Candida.
  • Dx: Symptoms + urine culture (≥10^3 CFU/mL with IUC).
  • Prevention: Aseptic insertion, closed drainage, daily necessity review, prompt removal. 📌 Avoid Unnecessary Catheters.

• CLABSI (Central Line-Associated Bloodstream Infection): Lab-confirmed BSI with CVC ≥2 days.

  • Pathogens: CoNS (Coagulase-Negative Staphylococci), S. aureus, Candida, Gram-negatives.
  • Dx: Positive blood culture(s). Differential Time to Positivity (DTP) >2 hrs (central vs. peripheral).
  • Prevention: Hand hygiene, chlorhexidine skin prep, optimal site selection, maximal barrier precautions, daily necessity review.

⭐ Daily review of CVC and urinary catheter necessity is crucial in preventing CLABSI & CAUTI.

Breath & Breach - Lung & Wound Woes

• Hospital-Acquired Pneumonia (HAP): Pneumonia developing ≥48h post-admission.
• Ventilator-Associated Pneumonia (VAP): Pneumonia developing >48-72h post-endotracheal intubation.
  • Early VAP (<5 days): S. pneumoniae, H. influenzae, MSSA.
  • Late VAP (≥5 days): P. aeruginosa, Acinetobacter spp., MRSA.
  • Diagnosis: New/progressive infiltrate + ≥2 clinical criteria (fever, leukocytosis, purulent sputum).
  • 📌 VAP Bundle: Key prevention strategy.

• Surgical Site Infection (SSI): Infection at/near surgical incision within 30 days (or 1 year if implant present).
  • Common Pathogens: S. aureus (most frequent), CoNS, Enterococci, E. coli.
  • Prevention: Pre-op antibiotics (e.g., Cefazolin) 30-60 min before incision. Vancomycin/Fluoroquinolones 120 min prior.

⭐ Most common organism causing SSI is Staphylococcus aureus. For most antibiotics, administer prophylaxis 30-60 minutes before skin incision to ensure adequate tissue concentration.

Gut Grumbles & Guard Up - C.diff & Control

• Clostridioides difficile Infection (CDI):

  • Risks: Antibiotics (clindamycin, FQs, 3rd gen cephalosporins), PPIs, ↑age, prolonged hospitalization.
  • Dx: Stool NAAT (toxin gene) + Toxin EIA (A/B). GDH antigen in algorithms.
  • Rx (Initial): Oral Vancomycin 125mg QID or Fidaxomicin 200mg BID for 10 days.
  • Rx (Recurrent): Vanco taper/pulse; Fidaxomicin; Fecal Microbiota Transplant (FMT).

  ⭐ For fulminant CDI (hypotension, shock, ileus, megacolon), use high-dose oral Vancomycin (500mg QID) + IV Metronidazole.

• HAI Prevention & Control:

  • Hand Hygiene: 📌 WHO 5 Moments. Soap & water for C.diff (alcohol ineffective).
  • Precautions: Standard for all. Contact for CDI (gown, gloves, isolation).
  • Antimicrobial Stewardship.
  • Environmental Disinfection: Sporicidal agents (bleach).

High‑Yield Points - ⚡ Biggest Takeaways

• UTI is the most common nosocomial infection, frequently catheter-associated (E. coli).
• HAP occurs >48h post-admission; VAP >48-72h post-intubation. Common: Pseudomonas, MRSA.
• CDI: Antibiotic-associated diarrhea; diagnose with stool toxin assay. Key: Clindamycin.
• SSI: Within 30 days post-surgery (or 1 year with implant); S. aureus is typical.
• CLABSI: Prevent with strict aseptic technique for central lines.
• Hand hygiene: The single most effective measure to prevent transmission.