Mycobacterium avium infection in Portugal

Although the incidence rates of non-tuberculous mycobacteria (NTM) have been increasing in many countries, the basic epidemiology of NTM remains to be fully understood.

To assess the incidence, clinical relevance and geographical distribution of NTM disease in Portugal and to identify demographic and clinical characteristics associated with Mycobacterium avium complex (MAC) disease.

Information stored in an electronic database of all NTM cases reported over an 11-year period was retrospectively reviewed. Significant demographic and clinical characteristics of MAC disease (vs. having any other NTM disease) were determined using multiple logistic regression models.

We identified 632 patients, mostly male, native Portuguese, with pulmonary disease, predominantly from Lisbon and Porto. The annual incidence of NTM disease was 0.54 per 100 000 population. The annual number of NTM cases increased throughout the study period. MAC was most frequently isolated. MAC disease was positively (and significantly) associated with being female, age >45 years and human immunodeficiency virus infection.

The increasing incidence of NTM over the study period emphasises the importance of NTM as a public health issue. This study provides important information for health care professionals and a basis for further study of NTM in Portugal.