Mycobacterium gordonae in fiberoptic bronchoscopes

Background: Failure of high-level disinfection of bronchoscopes has caused several outbreaks of nosocomial infection or pseudoinfection involving mycobacteria. Methods: Inocula (10⁵ colony-forming units/ml and 10⁸ colony- forming units/ml) of a clinical Mycobacterium gordonae isolate were used to contaminate bronchoscopes. Glutaraldehyde, iodophor, and peracetic acid disinfectants were evaluated in manual and automated disinfection procedures after 10- to 20-minute exposures at 20° and ≥25°C. Results: Four of five manual disinfectant procedures failed to eliminate experimental M. gordonae infection after 10-minute exposure at 20°C. All five manual procedures tested at 20°C were effective after 20-minute exposure to the life disinfectants (two 2% alkaline glutaraldehyde preparations, 3.2% alkaline glutaraldehyde, 75 ppm iodophor, and 0.5% glutaraldehyde-0.03% phenolic). Three of four manual (one 2% glutaraldehyde, 3.2% glutaraldehyde, and 0.5% glutaraldehyde-0.03% phenolic) and three automated (one 2% glutaraldehyde, 0.5% glutaraldehyde-0.03% phenolic, and 0.2% peracetic acid) disinfectant procedures eliminated contamination after a 10- to 12-minute exposure at ≥25°C. Effective total cycle times for the three automated procedures ranged from 20 to 45 minutes. Conclusions: Previously Environmental Protection Agency-approved tuberculocidal agents may be ineffective against M. gordonae when used according to label claims under normal clinical conditions. A minimum 20-minute exposure time at 20°C is necessary for manual disinfection methods. Higher temperatures may improve disinfectant efficacy. Newer automatic disinfection machines may be as effective as traditional manual methods and also may reduce hazards to employees.