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THE PERSISTENCE OF NONTUBERCULOUS MYCOBACTERIA INI A DRINKING WATER DISTRIBUTION SYSTEM AFTER THE ADDITION OF FILTRATION TREATMENT
Citation:
HILBORN, E., T. C. COVERT, S. HARRIS, S. F. DONNELLY, M. A. YAKRUS, E. W. RICE, S. TONEY, S. BAILEY, AND G. N. STELMA. THE PERSISTENCE OF NONTUBERCULOUS MYCOBACTERIA INI A DRINKING WATER DISTRIBUTION SYSTEM AFTER THE ADDITION OF FILTRATION TREATMENT. APPLIED AND ENVIRONMENTAL MICROBIOLOGY. American Society for Microbiology, Washington, DC, 72(9):5864-5869, (2006).
Impact/Purpose:
to determine if the prevalence of NTM recovered from an unfiltered surface drinking water system would decrease after the addition of ozonation and filtration treatment
Description:
There is evidence that drinking water may be a source of pathogenic nontuberculous mycobacteria (NTM) infections in humans. One method by which NTM are believed to enter drinking water distribution systems is by their intracellular colonization of protozoa. Our goal was to determine if the prevalence of NTM recovered from an unfiltered surface drinking water system would decrease after the addition of ozonation and filtration treatment. We sampled water from two initially unfiltered surface drinking water treatment plants over a 29-month period. One plant received the addition of filtration and ozonation after 6 months of sampling. Sample sites included those at treatment plant effluents, distributed water, and cold water taps (point-of-use (POU) sites) in public or commercial buildings located within each distribution systems. Overall prevalence of NTM for all sites was 25%. Water samples collected at POU sites yielded the majority of NTM, with a prevalence of greater than 50% despite the addition of ozonation and filtration. Closely related electrophoretic groups of M. avium were found to persist at POU sites for up to 26 months despite the addition of ozonation and filtration. Water collected from POU cold water taps was persistently colonized with NTM despite the addition of filtration to a drinking water system. This suggests that water distribution systems need to be considered as a potential source of chronic human exposure to NTM.