Antibiotic susceptibility of glutaraldehyde-tolerant Mycobacterium chelonae from bronchoscope washing machines.
BACKGROUND
Contamination of bronchoalveolar lavage fluid is a major problem in the world. Although 2% glutaraldehyde (GA) is widely used as a disinfectant for bronchoscope cleaning, recently, GA-tolerant mycobacteria have been isolated, which makes this problem more complicated.


METHODS
We studied the susceptibility to GA and antibiotics of mycobacteria isolated from bronchoscope washing machines in our hospital. We also studied the minimum inhibitory concentrations of GA and antibiotics with pump inhibitors.


RESULTS
Twenty-nine mycobacteria were isolated, of which 26 were Mycobacterium chelonae. Among 18 isolates of M chelonae, excluding 8 isolates in which some results were not reproducible, 50% (9 of 18) were 2% GA-tolerant. One hundred percent (9 of 9) of the GA-tolerant isolates and 11% (1 of 9) of the GA-sensitive isolates were either resistant or intermediately resistant to 2 or 3 classes of antibiotics. Efflux pump inhibitors did not influence the susceptibility to GA and antibiotics.


CONCLUSIONS
It was suggested that there might be an association of GA tolerance with antibiotic resistance in M chelonae. There may a different mechanism(s) other than that involving efflux pumps with regard to GA tolerance and antibiotic resistance in M chelonae. When bronchoscopy-related mycobacterial infections are suspected, physicians and clinical microbiologists should exercise care in handling GA-tolerant mycobacteria, which may be resistant to multiple antibiotics.
Nomura
Kazuyo
K
Department of Microbiology, University of Occupational and Environmental Health, School of Medicine, Kitakyushu, Japan.
Ogawa
Midori
M
Miyamoto
Hiroshi
H
Muratani
Tetsuro
T
Taniguchi
Hatsumi
H
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001992:Bronchoalveolar Lavage Fluid / Q000382:microbiology*; D020680:Bronchoscopes; D004202:Disinfectants; D024881:Drug Resistance, Bacterial; D004866:Equipment Contamination; D005976:Glutaral / Q000494:pharmacology*; D006801:Humans; D008826:Microbial Sensitivity Tests; D009165:Mycobacterium Infections, Nontuberculous / Q000517:prevention & control; D016926:Mycobacterium chelonae / Q000187:drug effects* / Q000302:isolation & purification*; D012680:Sensitivity and Specificity
D000900:Anti-Bacterial Agents; D004202:Disinfectants; D005976:Glutaral