Nosocomial contamination of laryngoscope handles: challenging current guidelines

Laryngoscope blades are often cleaned between cases according to well-defined protocols. However, despite evidence that laryngoscope handles could be a source of nosocomial infection, neither our institution nor the American Society of Anesthesiologists has any specific guidelines for handle disinfection. We hypothesized that laryngoscope handles may be sufficiently contaminated with bacteria and viruses to justify the implementation of new handle-cleaning protocols.

Sixty laryngoscope handles from the adult operating rooms were sampled with premoistened sterile swabs. Collection was performed between cases, in operating rooms hosting a broad variety of subspecialty procedures, after the room and equipment had been thoroughly cleaned for the subsequent case. Samples from 40 handles were sent for aerobic bacterial culture, and antimicrobial susceptibility testing was performed for significant isolates. Samples from 20 handles were examined for viral contamination using a polymerase chain reaction assay that detects 17 respiratory viruses.

Of the 40 samples sent for culture, 30 (75%) were positive for bacterial contamination. Of these positive cultures, 25 (62.5%) yielded coagulase-negative staphylococci, seven (17.5%) Bacillusspp. not anthracis, three (7.5%) alpha-hemolytic Streptococcusspp., and one each (2.5%) of Enterococcusspp., Staphylococcus aureus(S. aureus), and Corynebacteriumspp. No vancomycin-resistant enterococci, methicillin-resistant S. aureus, or Gram-negative rods were detected. All viral tests were negative.

We found a high incidence of bacterial contamination of laryngoscope handles despite low-level disinfection. However, no vancomycin-resistant enterococci, methicillin-resistant S. aureus, Gram-negative rods, or respiratory viruses were detected. Our results support adoption of guidelines that include, at a minimum, mandatory low-level disinfection of laryngoscope handles after each patient use.