Nontuberculous mycobacteria in Australians with cystic fibrosis: A national survey

Abstract

Aim: Understand the factors contributing to NTM acquisition and disease progression in Australians with CF. Methods: Nationally, 18 CF services collected respiratory samples from people with CF for NTM culture (baseline, 6 months, 1 year, annually to 4 years); linked with clinical, geographic and social data. Laboratories performed all culturing as a standard care test. An aliquot of respiratory sample was collected at baseline for microbiome analysis and Mycobacterium abscessus (Mabs) isolates stored for whole genome sequencing (WGS). Results: It took 18 months for all sites to commence recruitment (approvals for 15 hospitals and 13 labs took 24 months). Sample collection spanned from December 2016 to 31 December 2021. A shift to a virtual model of care during the pandemic and increased modulator therapy use (27% of recruits in 2017 to 57% in 2021) adversely impacted sampling. The study protocol was amended to allow collection of retrospective NTM culture data for samples collected outside study timepoints (ongoing). At October 2022, all participants (n = 1330) have at least one NTM culture, median 7 cultures/participant over a median 2.5 years. Cumulatively, 263 recruits have cultured NTM (19.8%). Of the NTM+ recruits, 31.2% had Mabs isolated, 32.7% had M. avium complex (MAC) species isolated and a further 8.4% had both Mabs and MAC organisms. Number and type of 'other NTM' species cultured varied across the states. Sputum aliquots have been collected from 1001 participants and 168 Mabs isolates have undergone WGS. Conclusion: Mabs and MAC infections are equally prevalent in our cohort. There is heterogeneity in methodology employed by the laboratories performing NTM culture, our preliminary results suggest that the laboratories utilising less rigorous methods of decontamination and/or highly selective media see a greater variety of 'other NTM' species. Data collection will be finalised December 2022.