Mycobacterium gordonae in fiberoptic bronchoscopes

Failure of high-level disinfection of bronchoscopes has caused several outbreaks of nosocomial infection or pseudoinfection involving mycobacteria.

Inocula (10(5) colony-forming units/ml and 10(8) 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 degrees and > or = 25 degrees C.

Four of five manual disinfectant procedures failed to eliminate experimental M. gordonae infection after 10-minute exposure at 20 degrees C. All five manual procedures tested at 20 degrees C were effective after 20-minute exposure to the five 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 > or = 25 degrees C. Effective total cycle times for the three automated procedures ranged from 20 to 45 minutes.

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 degrees 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.