Clinical features of respiratory nontuberculous mycobacteria – a four-year comparison by immunosuppression status

Abstract

Introduction: Immunosuppression(IS) is a key risk factor for nontuberculous mycobacteria(NTM) pulmonary infections. However, underlying lung disease is considered a major determinant of clinical features of pulmonary NTM disease. Aims and Objectives: Analyze whether IS status is associated with distinct clinical, radiological and microbiological presentations and survival outcomes of respiratory NTM. Methods: Cross-sectional study including patients with at least one positive respiratory NTM culture from 2014 to 2017(N=95) in a University Hospital Centre. 11 patients with unknown IS status were excluded. IBM® SPSS® Statistics was used for comparison between IS and non-IS patients. Results: From the 84 patients analyzed, 47,6%(n=40) had IS due to: autoimmune diseases(37.5%,n=15), active neoplasms(55%,n=22), organ transplantation(5%,n=2), liver cirrhosis(12.5%,n=5), HIV infection with CD4+ Asthenia(45%,n=18,p=0,033), chronic cough, dyspnea, low-grade fever and cachexia were more prevalent in IS patients. Bronchiectasis, cavitation, nodules and fibrotic changes were less prevalent in lung CT scans of IS patients than non-IS patients. Slow-growing NTM were significantly more frequent in IS patients(92.3%,n=36,p=0,048). Cumulative survival after first respiratory NTM sample was consistently lower in IS patients(p=0.052). Conclusions: In IS patients, typical respiratory NTM symptoms are more prevalent, but classical radiologic findings appear less often than in non-IS patients. These findings highlight the importance of clinical history for respiratory NTM suspicion in IS patients.