Genomic Analysis of Mycobacterium abscessus Complex Isolates Collected in Ireland between 2006 and 2017.

Members of the complex (MABC) are multidrug-resistant nontuberculous mycobacteria and cause opportunistic pulmonary infections in individuals with cystic fibrosis (CF). In this study, genomic analysis of MABC isolates was performed to gain greater insights into the epidemiology of circulating strains in Ireland. Whole-genome sequencing (WGS) was performed on 70 MABC isolates that had been referred to the Irish Mycobacteria Reference Laboratory between 2006 and 2017 across nine Irish health care centers. The MABC isolates studied comprised 52 isolates from 27 CF patients and 18 isolates from 10 non-CF patients. WGS identified 57 (81.4%) as subsp, 10 (14.3%) as subsp. , and 3 (4.3%) as subsp. Forty-nine (94%) isolates from 25 CF patients were identified as subsp, whereas 3 (6%) isolates from 2 CF patients were identified as subsp. Among the isolates from non-CF patients, 44% (8/18) were identified as subsp, 39% (7/18) were identified as subsp. , and 17% (3/18) were identified as subsp. WGS detected two clusters of closely related subsp isolates that included isolates from different CF centers. There was a greater genomic diversity of MABC isolates among the isolates from non-CF patients than among the isolates from CF patients. Although WGS failed to show direct evidence of patient-to-patient transmission among CF patients, there was a predominance of two different strains of subsp Furthermore, some MABC isolates were closely related to global strains, suggesting their international spread. Future prospective real-time epidemiological and clinical data along with contemporary MABC sequence analysis may elucidate the sources and routes of transmission among patients infected with MABC.