Non-tuberculous Mycobacterial Pseudo-outbreak of an Intestinal Culture Specimen Caused by a Water Tap in an Endoscopy Unit

Abstract

Objective Gastrointestinal lesions of non-tuberculous mycobacteria (NTM) are regarded as opportunistic infections. A large number of positive specimens of NTM were identified in an intestinal fluid culture in the endoscopy unit and it was considered to be a pseudo-outbreak. Methods We reviewed the hospital, laboratory, and colonoscopy records of 263 consecutive patients whose intestinal fluids were analyzed for a mycobacterial culture by colonoscopy at St. Marianna University Hospital, between January 2009 and December 2018. The endoscopy reprocessing procedures were reviewed and samples of water used in the endoscopy unit were cultured. Results An intestinal fluid culture of 154 (58.6%) patients tested positive for NTM (M. intracellulare; 125 cases, M. gordonae; 14 cases, M. avium; 4 cases, M. abscessus; 3 cases, and 8 other cases). In 182 cases (69.2%), an intestinal mucosal culture was performed simultaneously with a fluid culture and tested positive for NTM in 2 cases. Next, we examined the endoscopy unit for any possible environmental contamination. NTM were detected in the tap water used to prepare the antifoaming solution in the endoscopy unit. The water faucets in the endoscopy unit were considered to be the source of the contamination of NTMs. Conclusion We observed that a large number of cases tested positive due to contaminated water that had been used in an endoscopy unit, thus leading to a pseudo-outbreak of NTM.

Mitigation of nontuberculous mycobacteria in hospital water: challenges for infection prevention

“…If necessary to use in an emergency, the device should be positioned outside the operating room to prevent potentially contaminated aerosols from reaching the patient [13]. Purified water should be used to clean procedural tools, such as bronchoscopes and endoscopes, to minimize pseudooutbreaks [32][33][34].…”

“…Gastrointestinal and respiratory tracts are not only common gateways for NTM infection but also potential sites involved in pseudo-outbreaks. These pseudo-outbreaks have been controlled by replacement of contaminated equipment and use of sterile water for procedures [32][33][34]64]. Pseudo-outbreaks of NTM should be considered when an increase in positive cultures is not associated with compatible clinical disease.…”

“…NTM species identified in patients included Mycobacterium abscessus, Mycobacterium avium, M. gordonae, Mycobacterium intracellulare , and Mycobacterium peregrinum ; the source was identified to be water from two faucets in the endoscopy unit that were used to prepare the antifoaming solution. PCR identified the mycobacteria to the genera level, and restriction analysis was used for species identification [32]. A pseudo-outbreak of M. fortuitum in nine patients was reported in a bronchoscopy unit, which was linked to water from a tap used by the bronchoscope automated washing machine that was found not to have an antibacterial filter.…”

Isolation of Mycobacterium talmoniae from a patient with diffuse panbronchiolitis: a case report

“…The M. fortuitum group is a rare cause of pulmonary disease except in cases of achalasia and lipoid pneumonia [ 2 , 3 ]. M. gordonae most often represents tap water contamination [ 4 ]. In Japan, a recent study showed that MAC accounts for nearly 90% of all NTM cases [ 5 ].…”