Central line-associated bloodstream infections

CLABSI - The Unwanted Guest

• Pathogens: Coagulase-negative staph, S. aureus (incl. MRSA), Candida, Gram-negatives (Pseudomonas).
• Prevention is Key (Aseptic Technique):
  • Hand hygiene, full barrier precautions during insertion.
  • Chlorhexidine skin antisepsis.
  • Subclavian site preferred over jugular or femoral.
  • Daily review of line necessity.
• Diagnosis: Paired blood cultures (CVC & peripheral). Differential Time to Positivity (DTP) >2 hours is indicative.
• Management: Empiric vancomycin + anti-pseudomonal agent.

⭐ Always remove the line for S. aureus, Pseudomonas, Candida, or severe sepsis/shock.

Microbiology - The Usual Suspects

• Gram-Positive Cocci (>60%): Most common; originate from skin flora.
  • Coagulase-negative staphylococci (S. epidermidis)
  • Staphylococcus aureus (MSSA & MRSA)
  • Enterococcus spp. (VRE)
• Gram-Negative Rods:
  • Pseudomonas aeruginosa
  • Klebsiella pneumoniae
  • E. coli
• Fungi:
  • Candida spp. (esp. with TPN, broad-spectrum antibiotics)

⭐ Biofilm formation is a key virulence factor (S. epidermidis, Pseudomonas), making infections difficult to treat without catheter removal.

Prevention - Keeping Lines Clean

• Hand Hygiene: Crucial before any line contact. Use alcohol-based rub or soap and water.
• Aseptic Technique: Maintain strict sterile fields during catheter insertion, maintenance, and dressing changes.
• Skin Antisepsis: Prep insertion site with > 0.5% chlorhexidine in alcohol. Allow to air dry completely.
• Hub Care:
  • Vigorously "scrub the hub" with an antiseptic wipe (e.g., chlorhexidine, povidone-iodine, 70% alcohol) before each access.
  • Use disinfecting caps on needleless connectors.

⭐ Daily bathing with chlorhexidine gluconate (CHG) wipes in ICU patients can significantly ↓ the risk of CLABSI and acquisition of multidrug-resistant organisms.

Diagnosis - The Infection Detective

• Blood Cultures: The cornerstone of diagnosis. Obtain paired sets before starting antibiotics.
  • One set from a catheter hub.
  • One set from a peripheral vein.
• Key Diagnostic Criteria (requires one of the following):
  • Differential Time to Positivity (DTP): Central line culture flags positive ≥2 hours before the peripheral culture.
  • Quantitative Blood Culture: Colony count from central line is ≥3-fold higher than peripheral.
  • Catheter Segment Culture (Maki Roll): Growth of >15 CFUs on a rolled distal catheter tip.

⭐ DTP is the most specific non-invasive method for diagnosing CLABSI. Catheter tip culture requires line removal and can be prone to contamination.

Management - The Counterattack

• Empiric Antibiotics: Initiate immediately after obtaining blood cultures (from both the line and a peripheral vein).

  • Vancomycin or Linezolid (to cover MRSA).
  • Broad Gram-negative coverage: Cefepime, piperacillin-tazobactam, or a carbapenem, guided by local resistance data and patient severity.

• Catheter Management: The critical decision point.

⭐ Duration of therapy for uncomplicated CLABSI is 7-14 days, starting from the first day of documented negative blood cultures, not from the initiation of antibiotics.

• Antibiotic Lock Therapy: May be used alongside systemic antibiotics if attempting to salvage the catheter.

High-Yield Points - ⚡ Biggest Takeaways

• CLABSIs are a primary cause of nosocomial bloodstream infections.
• Most common pathogens: Coagulase-negative staphylococci, S. aureus, enterococci, and Candida.
• Prevention is paramount: strict aseptic technique, chlorhexidine skin prep, and full barrier precautions.
• Daily review of line necessity is crucial; remove catheters as soon as possible.
• Diagnosis: Differential time to positivity >2 hours between line and peripheral blood cultures.
• Management: Prompt line removal and empiric antibiotics are standard of care.