Infection by Clonally Related Mycobacterium abscessus Isolates: The Role of Drinking Water.

Rationale: Mycobacterium abscessus (MABS) group bacteria cause lethal infections in people with chronic lung diseases. Transmission mechanisms remain poorly understood; the detection of dominant circulating clones (DCCs) has suggested the potential for person-to-person transmission. Objectives: This study aimed to determine the role of drinking water in the transmission of MABS. Methods: A total of 289 isolates were cultured from respiratory samples (n = 231) and drinking water sources (n = 58) across Queensland, Australia. Measurements and Main Results: Whole-genome sequences were analyzed to identify DCCs and determine relatedness. Half of the isolates (n = 144; 49.8%) clustered with previously described DCCs, of which 30 formed a clade within DCC5. Pan-genomic analysis of the water-associated DCC5 clade revealed an enrichment of genes associated with copper resistance. Four instances of plausible epidemiological links were identified between genomically related clinical and water isolates. Conclusions: We provide evidence that drinking water is a reservoir for MABS and may be a vector in the chain of MABS infection.