Potable water as a possible source of mycobacterium abscessus infection in people with chronic lung conditions

Abstract

Introduction/Aim: Mycobacterium abscessus group (MABS) are emerging respiratory pathogens in people with underlying lung conditions. The acquisition and transmission of MABS infection is poorly understood. MABS has been detected in drinking water distribution systems (Thomson et al, BMC Infect Dis, 2013; Morimoto et al, ERJ Open Res, 2018). We aimed to determine the role of potable water in the acquisition and transmission of MABS respiratory infection. Methods: A total of 241 MABS respiratory isolates from 90 participants with chronic lung conditions (including cystic fibrosis and bronchiectasis) stored at Queensland Mycobacterium Reference Laboratory from 2000-2017 were compared with MABS isolates recovered from potable water sampling (n=52). The whole genome sequences of the clinical and environmental isolates were compared to determine their relatedness using published definitions (Bryant et al, Science, 2016). Results: Certain clinical and environmental isolates were closely related. Respiratory MABS isolates from unrelated people with chronic lung conditions were closely related to potable water MABS isolates suggesting a possible point source outbreak in the local water supply. Probable transmission events (<20 SNP) were observed in two people with CF and active MABS respiratory infection (<2 years since positive sputum culture) whose homes had MABS detected in the water. The home water MABS isolates when compared to the home occupier's respiratory isolate(s) were separated by a maximum of 1 SNP and 17 SNPs, respectively. The direction of infection, patient-to-environment or environment-topatient, could not be inferred. Conclusion: The environment is a likely source of MABS. Wider environmental sampling, combined with extended sequencing comparisons with clinical (including extra-pulmonary) MABS isolates, is required to determine the role of the environment (particularly direction of transmission) in the spread of MABS pulmonary and extra-pulmonary infection.L6269391582019-04-02 <br />