Disinfection of bronchoscopes, contaminated in vitro with Mycobacterium tuberculosis, Mycobacterium avium-intracellulare and Mycobacterium chelonae in sputum, using stabilized, buffered peracetic acid solution ('Nu-Cidex')

The efficacy of 0.35% stabilized buffered peracetic acid solution ('Nu-Cidex') against clinical isolates of Mycobacterium tuberculosis, Mycobacterium avium-intracellulare and Mycobacterium chelonae in homogenized sputum was tested. An in-use method, using an automated bronchoscope washing machine, showed that over 10 cycles, at a disinfectant contact time of 5 min, M. tuberculosis and M. chelonae were effectively eradicated from the bronchoscope, even in the absence of detergent and pre-cleaning. M. avium-intracellulare was not eradicated in only one of 10 cycles with contact times of 5 and 10 min, but numbers were reduced by >7 log(10) and >5 log(10), respectively. With detergent present, M. avium-intracellulare was successfully eradicated in all cycles at a contact time of 5 min or greater. The results demonstrate that peracetic acid is an effective mycobactericidal agent for use in the disinfection of bronchoscopes.