Nontuberculous mycobacteria: incidence in Southwest Ireland from 1987 to 2000

Setting: The Southwest of Ireland (Counties Cork and Kerry) 1987–2000, average population 549 500. Objective: Nontuberculous mycobacteria (NTM) cause significant morbidity worldwide and the study of epidemiology and characteristics helps in their prevention and treatment. This study was performed to determine the incidence of NTM disease in comparison to Mycobacterium tuberculosis ( M. tuberculosis ) and Mycobacterium bovis ( M. bovis ) in Southwest Ireland, over the above time period. Design: A retrospective study was carried out in all human isolates of NTM, M. tuberculosis and M. bovis between 1987 and 2000, in the Southwest Region of Ireland. Results: The mean incidence of NTM (0.4/100 000 population) has risen since 1995, principally of pulmonary Mycobacterium avium intracellulare complex (MAC). The annual incidence of M. tuberculosis in humans over 14 years in the same region was 9.71/100 000 population with a significant reduction since 1994 and M. bovis remained constant at 0.5/100 000 population. Conclusion: The increasing incidence of disease causing NTM noted in Southwest Ireland reflects global data and is surmised to be due to an ageing population, increased incidence related to chronic fibrotic lung disease, and environmental mycobacterial factors.