Distribution and outcomes of infection of Mycobacterium avium complex species in cystic fibrosis

BackgroundThe majority of nontuberculous mycobacterial (NTM) pulmonary infections in people with cystic fibrosis (CF) are caused by Mycobacterium avium complex (MAC) species. Data on MAC species distribution and outcomes of infection in CF are lacking.MethodsThis was a single center, retrospective study. MAC isolates had species identification with MLSA of rpoB and the 16S23S ITS region. Clinical data were compared between species.ResultsTwenty-three people with CF and 57 MAC isolates were included. Infection with M. avium was the most common (65.2%). M. intracellulare was associated with higher rates of NTM disease, younger age, and steeper decline in lung function prior to infection.ConclusionsWe observed worse clinical outcomes in people with M. intracellulare infection relative to other MAC species. Further investigation of clinical outcomes of MAC infection among CF patients is warranted to better define the utility of species-level identification of MAC isolates in CF.