Genomic Epidemiology ofMycobacterium abscessusat an Adult Cystic Fibrosis Program Reveals Low Potential for Healthcare-Associated Transmission

Abstract

RationaleNontuberculous mycobacteria (NTM) has been reported to be transmitted between people with cystic fibrosis (pwCF) attending Cystic Fibrosis (CF) Centers. 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.ObjectivesApply 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 pwCF infected with genetically similar NTM isolates.MethodsWhole genome sequencing (WGS) of respiratoryM. abscessusisolates from 50 pwCF receiving care at UTSW was performed to identify genetically similar isolates. Epidemiological investigation, comparison of respiratory and environmental isolates, and home residence watershed mapping were studied.Measurements and Main ResultsWGS 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 patient-to-patient transmission ofM. abscessusappears rare at this Center. However, polyclonal infections ofM. abscessusspecies and subspecies, not originating from the endemic hospital environment, suggests multiple shared modes of acquisition outside the healthcare setting.