Epidemiology, microbiological characteristics and risk factors of non-tuberculous mycobacterial respiratory infections in adult patients with cystic fibrosis

<bold>Background:</bold> The increasing prevalence of non-tuberculous mycobacterial (NTM) infections is an emerging problem in cystic fibrosis (CF) due to the suboptimal treatment options and high relapse rates. Current studies report prevalence rates of sputum NTM ranging from 3.7% to 13.9%. <bold>Methods:</bold> Data on systematic NTM surveillance of 147 CF patients were collected retrospectively and evaluated by case-control analysis between 2020 and 2022. The evaluation focused on demographic, clinical, and microbiological data to determine the risk potential for NTM acquisition. The analysis also included the distribution of NTM species and their susceptibility to antibiotics. <bold>Results:</bold> In 2022, the prevalence of NTM-positive sputum was 18.4%. The most common NTM species were Mycobacterium avium complex (MAC) (40.6%), Mycobacterium abscessus complex (MABSC) (37.5%), and Mycobacterium xenopi (15.6%). MABSC strains demonstrated high resistance to doxycycline, ciprofloxacin, imipenem, and sulphonamides (100, 100, 81.25 and 81.25%, respectively). Previous NTM-positive sputum enhanced the risk of subsequent NTM respiratory colonisation (odds ratio: 5.41). The mean forced expiratory volume in one second (FEV1) of the cases was significantly lower than that of the controls even one and two years before the detection of NTM (p<0.01). <bold>Conclusion:</bold> The results demonstrate an increased prevalence of NTM in the Hungarian adult CF population and a high rate of multidrug-resistant MABSC isolates in their sputum. Patients with significantly impaired lung function and previous respiratory mycobacteriosis are at a higher risk of acquiring NTM airway colonisation.