Global trends of pulmonary infections with nontuberculous mycobacteria: a systematic review

•Nontuberculous mycobacteria (NTM) are increasingly recognized as important opportunistic pathogens.•Most studies report increasing trends of pulmonary NTM infection and disease.•Data on NTM trends are limited in their geographical representation.•More evidence is required to explain this increase seen worldwide. To describe the global trends of pulmonary nontuberculous mycobacteria (NTM) infection and disease. A systematic review of studies including culture-based NTM data over time. Studies reporting on pulmonary NTM infection and/or disease were included. Information on the use of guideline-based criteria for disease were collected, in which, infection is defined as the absence of symptoms and radiological findings compatible with NTM pulmonary disease. The trends of change for incidence/prevalence were evaluated using linear regressions, and the corresponding pooled estimates were calculated. Most studies reported increasing pulmonary NTM infection (82.1%) and disease (66.7%) trends. The overall annual rate of change for NTM infection and disease per 100,000 persons/year was 4.0% (95% confidence interval [CI]: 3.2-4.8) and 4.1% (95% CI: 3.2-5.0), respectively. For absolute numbers of NTM infection and disease, the overall annual change was 2.0 (95% CI: 1.6-2.3) and 0.5 (95% CI: 0.3-0.7), respectively. An increasing trend was also seen for Mycobacterium avium complex infection (n = 15/19, 78.9%) and disease (n = 10/12, 83.9%) and for Mycobacterium abscessus complex (n = 15/23, 65.2%) infection (n = 11/17, 64.7%) but less so for disease (n = 2/8, 25.0%). Our data indicate an overall increase in NTM worldwide for both infection and disease. The explanation to this phenomenon warrants further investigation.