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used to rinse bronchoscopes during reprocessing and resultant contamination of the bronchoscopes themselves. Bronchoscopy clinics, particularly those with high volume
and/or that serve immunocompromised patients, should pro- spectively review BAL cultures to identify unexpected pathogen trends. Our pseudo-outbreak may have been recognized and terminated sooner had routine surveillance of culture results from the bronchoscopy clinic been performed. The molecular data suggests that the pseudo-outbreak likely began earlier than it was clinically recognized. Endoscope-related pseudo-outbreaks, including those caused
by NTM, continue to occur despite standardized procedures for high-level disinfection of endoscopes. Mycobacterium avium and other NTM species, including M. chimaera and M. absces- sus, are known to colonize household and municipal water.10 Based on our findings, we recommend that routine maintenance schedules for AERs and endoscopes be adjusted based on usage and local water quality rather than a fixed time schedule. Additionally, new technologies, such as disposable endoscopes or endoscopes that can be sterilized, are needed to improve the safety of these devices. Our study had some limitations. First, differentiating MAC
clinical infection from colonization is challenging, particularly in lung transplant patients. Therefore, we were not able to calculate incidence rate of MAC infection in the baseline and outbreak periods. However, the significantly lower proportion of patients who received treatment for MAC disease supports the hypothesis that this was a pseudo-outbreak rather than true outbreak. Second, the filter change frequency from quarterly to monthly was instituted for all 3 filter sizes.We did not experiment with varying the timing of only the terminal filter change, nor did we confirm the exact time at which the filters failed. Finally, molecular sequencing was performed on only a convenient sample of isolates from each study period; therefore, we did not determine the true prevalence of the pseudo-epidemic clone in BALs performed throughout the study period. The molecular data show a decrease in recovery of the M. avium pseudo-epidemic clone after the adoption of monthly filter changes. We are unable to determine whether the ongoing recovery of the pseudo-epidemic clone VNTR no. 51 represents ongoing low-level contamination of rinse water or simply indicates that VNTR no. 51 is present in the local municipal water supply and causes colonization or infection in patients when patients are exposed to municipal water via other routes. In conclusion, we describe a pseudo-outbreak of a single clone of M. avium related to failure of the AER rinse water
Jessica L. Seidelman et al
filtration system. Healthcare facilities performing high-volume endoscopy procedures should be aware that AER filters may require replacement based on frequency of use or water quality rather than manufacturers’ recommendations based on time in use.
Acknowledgments. None. Financial support. No financial support was provided relevant to this article.
Conflicts of interest. All authors report no conflicts of interest relevant to this article.
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