High incidence of non-tuberculous mycobacteria-positive cultures among children with cystic fibrosis in australia

Abstract

Chronic nontuberculous mycobacteria (NTM) infections have rapidly emerged in people with CF, posing a significant threat to their survival. This prospective study aims to determine the prevalence and incidence of NTM in Australia as part of the ongoing National NTM in CF study. A risk-based cohort study is underway in 19 CF centres in Australia. Recruits are consenting adult or paediatric individuals with CF who produce a respiratory sample as part of a routine clinical visit (sputum, bronchoalveolar lavage or induced sputum). Samples are collected at baseline, six and 12 months and sent for mycobacterial culture. Nationally 576 adult and 341 paediatric recruits have provided up to 3 sputum samples for mycobacterial culture (September 2016 - Mar 2019). Preliminary findings indicate that in the national cohort of the NTM in CF study, NTM infection is higher in paediatric (12.9%) compared to adult recruits (8.1%). Mycobacterium abscessus group (MABS) infections (57.9%) are the predominant NTM infection in paediatric recruits followed by M. avium complex (MAC) infections (35.1%). In contrast, MAC species are the most commonly isolated NTM species (46.6%) in adults, followed by MABS (39.7%). This pattern of infection varies from state to state within Australia. In the National cohort, NTM-positive recruits are significantly younger than the NTM-negative recruits (p< 0.05). Recruits infected with MABS have a significant reduction in mean FEV1% predicted (60.7% ± 20.0 SD) when compared to age-matched NTM-negative recruits (66.6% ± 19.3 SD) (p<0.05). Younger people with CF are more likely to acquire MABS. Participants with MABS infections have reduced lung function compared to age-matched peers without NTM infections or those infected by slow-growing mycobacterial species. It is not known if poor lung function is a marker for acquisition of MABS or a result of MABS infection.L6293886982019-09-26 <br />