Mycobacterium abscessus: Acquisition and transmission pathways

Abstract

Introduction/Aim: The environmental bacterium Mycobacterium abscessus (Mabs) presents an infection risk to immunocompromised people. It is difficult to eradicate, requiring prolonged antibiotic treatment. The prevalence of Mabs is increasing globally but the reasons for this are poorly understood. Person-to-person transmission and environmental exposure (including fomite contact) have been suggested as possible acquisition routes. The overarching aims of Mycobacterium abscessus acquisition from potable water (MAP) study is to understand the acquisition pathways for Mabs, investigate transmission from water and person-to-person exposures and determine ways to reduce the exposure of at-risk individuals. Methods: MAP comprises of four distinct studies addressing these aims: Determining the evolution of Mabs: Comparing the genetic make-up of historical and recent Mabs infections. Identifying possible environmental sources of Mabs: Sampling water from hospitals and the homes of people with Mabs pulmonary disease (Mabs-PD). Sampling along the drinking water distribution system (DWDS). Genetic comparison of clinical with environmental Mabs Exploring possible transmission routes of Mabs: Investigating cough aerosol transmission as a potential route of Mabs cross-infection by studying people with CF and Mabs-PD. Investigate the extent to which Mabs form biofilms in an in vitro plumbing model, and then determine if disinfection of the plumbing systems can control the growth of Mabs. Results: To date 278 of 368 taps have been sampled from hospital (166/200) and DWDS (112/168). Analysis of finalised samples (hospitals n = 118, DWDS n = 42) determined Mabs was present in two hospital and seven DWDS taps. Thirty-five of 75 participant homes have been sampled. Of the 148 taps sampled, 81 have been finalised and Mabs isolated from 20 taps representing 11 homes. Conclusion: Mabs was present in hospital and DWSD it is most prevalent in home water. The genetic linkage of historical with recent isolates, and environment with clinical isolates is ongoing.