Infection by Clonally Related <i>Mycobacterium abscessus</i> Isolates: The Role of Drinking Water.

Abstract

<b>Rationale:</b> <i>Mycobacterium abscessus</i> (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. <b>Objectives:</b> This study aimed to determine the role of drinking water in the transmission of MABS. <b>Methods:</b> A total of 289 isolates were cultured from respiratory samples (<i>n</i> = 231) and drinking water sources (<i>n</i> = 58) across Queensland, Australia. <b>Measurements and Main Results:</b> Whole-genome sequences were analyzed to identify DCCs and determine relatedness. Half of the isolates (<i>n</i> = 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. <b>Conclusions:</b> We provide evidence that drinking water is a reservoir for MABS and may be a vector in the chain of MABS infection.