Geographical distribution and clinical relevance of non-tuberculous mycobacteria in Croatia

SETTING: The clinical relevance of non-tuberculous mycobacteria (NTM) in Croatia is unknown. OBJECTIVE: To estimate the isolation rate of NTM, record geographical differences and assess the burden of pulmonary NTM disease in Croatia. DESIGN: Nationwide retrospective cohort study of all Croatian residents with NTM isolated by culture in the period from 2006 to 2010. Microbiological criteria of the American Thoracic Society were used to establish a laboratory-based case definition of possible and probable NTM disease. RESULTS: Of 1187 individuals with pulmonary NTM isolates, 8.6% met the possible and 5.5% met the probable disease criteria. We estimated an annual incidence of probable pulmonary NTM disease of 0.23 per 100 000 population. This estimated annual incidence was 0.35/100 000 in the coastal region and 0.17/100 000 in the continental region. Species distribution differed between coastal and continental Croatia. NTM isolation frequency increased over the study period. CONCLUSION: Geography plays an important role in NTM species distribution and possible disease. The overall burden of NTM pulmonary disease in Croatia is still low compared to that of tuberculosis, but it is higher in the coastal region compared to the continental region.