Abstract

Background: Nontuberculous mycobacteria (NTM) comprise a group of over 190 species described to date and can produce a wide spectrum of clinical presentations. Although the prevalence of these infections is increasing globally, their diagnosis and treatment remain a challenge. Aim: To describe the clinical and epidemiological profile of infections caused by NTM in a 21-year period in Chile. Methods: A retrospective, descriptive analysis based on all NTMpositive cultures analyzed by the Microbiology Laboratories at Red de Salud UC-CHRISTUS, between May 2000 and October 2021. Results: A total of 260 positive NTM cultures were found in the study period, 163 (62.7%) originated from pulmonary and 97 (37.3%) from extrapulmonary sources. Slow-growing species accounted for 188 (72.3%) and fast-growing species accounted for 49 (19.8%) of the isolates. Mycobacterium avium (45.2%) and M. abscessus (26.5%) were the most frequent species in each group, respectively. The odds of having a structural lung disease (OR 24.20, IC 95% 3.23-181.00), a chronic respiratory disease (OR 12.60, IC 95% 3.75-42.30), a chronic cardiovascular disease (OR 4.71, IC 95% 1.89-11.80) or a gastroesophageal reflux disease (GERD) (OR 4.69, IC 95% 1.35-16.30) were significantly higher in patients with pulmonary NTM disease than in patients with extra-pulmonary NTM disease. Patients living with human immunodeficiency virus (HIV) had a significantly higher risk of bacteriemia (OR 11.60, IC 95% 4.74-28.30) but a lower risk of pulmonary disease (OR 0.22, IC 95% 0.11-0.42), than those non- HIV-infected. Conclusions: M. avium andM. abscessus were the most frequent species in NTM infections. Furthermore, structural pulmonary diseases, chronic respiratory diseases, chronic cardiovascular diseases, GERD and HIV infection were identified as significant associations for specific clinical presentations.