Prevalence and factors associated with nontuberculous mycobacteria in non-cystic fibrosis bronchiectasis: a multicenter observational study

BACKGROUND Data on the prevalence of and factors associated with nontuberculous mycobacteria (NTM) in patients with non-cystic fibrosis (CF) bronchiectasis are limited. Our aim was to determine the prevalence and factors associated with isolation of NTM in this population. METHODS We performed a multicenter observational study of historical cohorts comprising consecutive patients with non-CF bronchiectasis and at least 2 sputum samples cultured for mycobacteria over a period of 5 years. RESULTS The study population included 218 adult patients (61.9 % women) with a mean (SD) age of 55.7 (16) years and a mean (SD) of 5.1 (3.3) cultures/patient. NTM was isolated from sputum in 18 patients (8.3 %). Of these, 5 patients (28 %) met the American Thoracic Society criteria for NTM disease. Mycobacterium avium complex was the most frequently isolated microorganism (9 patients, 4.1 %). The variables independently associated with isolation of NTM were FVC ≥ 75 % predicted (OR, 4.84; 95 % CI 1.47 to 15.9; p < 0.05), age ≥ 50 years (OR, 4.74; 95 % CI 1.25 to 17.97; p < 0.05), and body mass index (BMI) ≤ 23 kg/m(2) (OR, 2.97; 95 % CI 1.03-8.58; p < 0.05). Patients with these three characteristics had a 40 % probability of having at least one isolation of NMT. CONCLUSIONS A significant number of patients with non-CF bronchiectasis are positive for the isolation of NTM. M. avium complex is the most frequently isolated mycobacteria. FVC ≥ 75 % predicted, age ≥ 50 years, and a BMI ≤ 23 kg/m(2) were independently associated with the presence of NTM in patients with non-CF bronchiectasis.