Non-tuberculous mycobacteria in HIV-negative patients with pulmonary disease in Lisbon, Portugal

Non-tuberculous mycobacteria (NTM) are responsible for an increase in mycobacterial disease in many developed countries. However the epidemiology, especially in patients without HIV infection, remains difficult to determine. We studied a convenience sample of 5497 HIV-negative patients receiving care at our pneumology centres. Among 510 patients with mycobacterial isolates, NTM were demonstrated in 58, all showing signs of lung disease. The mycobacteria isolated were M. intracellulare (n = 9, 15.5%), M. fortuitum (n = 8, 13.8%), M. gordonae (n = 7, 12.1%), M. kansasii (n = 6, 10.3%), M. chelonae (n = 5, 8.6%), M. avium (n = 4, 6.9%), M. abscessus (n = 3, 5.2%), M. peregrinum (n = 3, 5.2%), M. triplex (n = 3, 5.2%), M. spp. (n = 3, 5.2%), M. szulgai (n = 3, 5.2%), M. mucogenicum (n = 2, 3.4%), M. lentiflavum (n = 1, 1.7%) and M. simiae (n = 1, 1.7%). The present high percentage of NTM strains among mycobacterial isolates (approximately 11%), suggests the emergence of NTM infections as a public health problem. Larger, multicentre and multiregional studies or mandatory reporting will be required to better understand the changing epidemiology of NTM in patients with lung disease.