[Nontuberculous mycobacteria in wet areas of a hospital and standard residences].

From 1998 to 2000, UOEH Hospital identified a problem with bronchoscopes which were contaminated with mycobacteria. While conducting research into the problem, we found an extensive amount of nontuberculous mycobacteria (NTM) in wet areas. In this study, we collected a total of 114 samples to screen wet areas such as drains and taps in our hospital and in standard residences. We used the Ziehl-Neelsen staining method and specific PCR for mycobacteria. As a result, mycobacteria were detected in 96% (27/28) of hospital samples and 40% (34/86) of standard residential samples. Next, we tried to isolate mycobacteria. Eleven isolates from hospital samples and 24 isolates in standard residential samples were isolated through cultivation. Seventeen isolates of Mycobacterium gordonae were isolated. Four isolates of M avium were isolated exclusively in hospital samples. Three isolates of M. avium were resistant to 8 antimicrobial agents, including antituberculous agents. Two hospital isolates survived in phagocytes. Although 80% ethanol solution was effective in all 13 tested isolates, it was not effective in decontaminating the one drain we tested. After brushing the drain with 80% ethanol solution, mycobacteria were not detected for 3 months. This indicated to us that brushing with 80% ethanol solution was an effective procedure for eradicating mycobacteria.