Global Epidemiology of Nontuberculous Mycobacterial Pulmonary Disease: A Review

NTM-PD and NTM pulmonary isolation are increasing in most countries and regions globally. Isolate-based analysis in several countries indicates distinct trends by NTM species, highlighting the need for more species-specific analyses in NTM epidemiology. Available data regarding spe-cies indicates that MAC continues to predominate in most regions, although in Ontario, Canada, and distinct European countries M kansasii, M xenopi, and M malmoense are found with greater fre-quency. Variation in methods and case definitions limit comparisons across countries and regions. Population-based data including incidence and/ or prevalence are available from North America, Europe, East Asia (Japan, South Korea, and Taiwan), and Queensland, Australia. Studies from Central and South America, Africa, China, the Mid-dle East, and South Asia (India) among patients with suspected TB and MDR-TB are important to document the burden of undiagnosed NTM in this population and ensure appropriate treatment. This highlights the need for enhanced mycobacte-rial laboratory capacity to discriminate between cases of TB and NTM by routine speciation of mycobacterial isolates. Clinical data available from several regions have allowed better charac-terization of the affected populations. Across regions, the majority of cases occur among per -sons aged older than 50 years. In North America and East Asia, the proportion with COPD is typi-cally less than 20%, whereas in Europe, the pro-portion with COPD is higher, above 30% in 9 of 13 studies with this information. Implementation of surveillance systems with standard case definitions is needed to allow for global comparison of prevalence and trends. Cur-rent data where NTM-PD is a notifiable condition have shown the importance and utility of these surveillance data. In particular, timely notification data have allowed inference of the incubation period for infection and disease and have further allowed identification of specific high-risk environ-mental niches and environmental risk factors.