[Isolation of nontuberculous mycobacteria during colonoscopy]

We conducted a survey on nontuberculous mycobacteria (NTM) isolated in association with colonscopy at two hospitals. NTM was isolated from the fluid-phase of colonic contents in 17.6% of the specimens obtained at hospital A and in 46.3% at hospital B. The rate of isolation from the preexamination suction fluid was 9.5% and 43.3% at hospital A and B, respectively. Tap water samples from both hospitals were examined and proved to be free from contamination with NTM. The mycobacterial species isolated at hospital A were M. chelonae subsp. abscessus, M. chelonae subsp. chelonae, M. fortuitum, and M. gordonae. M. chelonae subsp. abscessus was the only mycobacterial species isolated at hospital B. M. avium complex was not isolated at either hospital. By an additional procedure to cleans and decontaminate the endoscopes by suction with Maskin ethanol solution, the incidence of isolation of NTM from the fluid-phase of colonic contents was significantly reduced. None of the patients from whom NTM was isolated exhibited positive signs of colonic NTM infection by the endoscopic examination and non had any underlying diseases which might induce immune suppression. We suspect that most of the NTM isolates have originated from the contaminated endoscope. In conclusion, when a colonscopic examination is carried out in suspicion of NTM disease in intestine, it is essential to reassess the possibility of mycobacterial contamination of the colonscopes and implement appropriate steps for cleansing and sterilization of them.