Genomic epidemiology ofMycobacterium abscessusat an adult cystic fibrosis programme reveals low potential for healthcare-associated transmission

Abstract

RationaleNontuberculous mycobacteria (NTM) has been reported to be transmitted between people with cystic fibrosis (CF) attending CF centres. A suspectedMycobacterium abscessusoutbreak was investigated at the University of Texas Southwestern (UTSW) Adult CF Program using a combination of pathogen genomic sequencing and epidemiologic methods. The objectives of the present study were to apply the Healthcare-Associated Links in Transmission of NTM (HALT NTM) study to investigate the occurrence of potential healthcare-associated transmission and/or acquisition of NTM among people with CF infected with genetically similar NTM isolates.MethodsWhole-genome sequencing of respiratoryM. abscessusisolates from 50 people with CF receiving care at UTSW was performed to identify genetically similar isolates. Epidemiologic investigation, comparison of respiratory and environmental isolates, and home residence watershed mapping were studied.Measurements and main resultsWhole-genome sequencing analysis demonstrated seven clusters of genetically similarM. abscessus(four ssp. abscessusand three ssp.massiliense). Epidemiologic investigation revealed potential opportunities for healthcare-associated transmission within three of these clusters. Healthcare environmental sampling did not recoverM. abscessus, but did recover four human disease-causing species of NTM. No subjects having clustered infections lived in the same home residence watershed. Some subjects were infected with more than oneM. abscessusgenotype, both within and outside of the dominant circulating clones.ConclusionsHealthcare-associated person-to-person transmission ofM. abscessusappears to be rare at this centre. However, polyclonal infections ofM. abscessusspecies and subspecies, not originating from the endemic hospital environment, suggest multiple shared modes of acquisition outside the healthcare setting.