Nontuberculous mycobacterial disease in North America

IntroductionNontuberculous mycobacteria (NTM) are ubiquitous in the environment and exist as important causes of pulmonary infections in human. Pulmonary involvement is the most common disease manifestation of NTM and the incidence of NTM is growing in the North America. Susceptibility to NTM infection is incompletely understood and, therefore preventative tools are not well defined. Treatment of pulmonary nontuberculous mycobacterial (NTM) infection is difficult and entails multiple antibiotics and an extended treatment course. Also, there is a considerable variation in treatment management that should be considered before initiating treatment.Material and methodsA literature search was conducted using search keywords “nontuberculous mycobacteria,” “MAC,” “M. abscessus,” “epidemiology,” “treatment,” “North America,” “mortality,” “cystic fibrosis,” “transplantation,” “prevention,” and “diagnosis” from studies that have been published between the years 2009 and 2014. PubMed, Cinahl, Scopus, Embase, and the Cochrane Library were searched. A total of 382 articles were reviewed from which 65 papers met our selection criteria. Titles of interest were further reviewed by all authors. Reference lists of relevant studies were hand-searched in order to identify other potentially relevant articles. Studies included in this review met the following criteria: (i) study populations included patients with NTM; (ii) articles were full reports, case reports or reviews; (iii) articles were in English and published from the US based institutes; (iv) articles were published in peer-reviewed journals.ResultsNontuberculous mycobacteria (NTM) are an important cause of morbidity and mortality, often in the form of progressive lung disease. Few reports are accessible on NTM disease prevalence in the United States; however based on the recent data the incidence and mortality rates of pulmonary NTM have been reported to be rising in North America. We highlight the new findings in the epidemiology, diagnosis and treatment of mycobacterial infections. We debate new advances regarding NTM infection in cystic fibrosis patients and solid organ transplant recipients. Finally, we introduce a new epidemiologic model for NTM disease based on virulence–exposure–host factors.ConclusionIt is critical that NTM is recognized as an important public health issue with potentially significant consequences for affected patients. Finally, the applicability of the virulence–exposure–host model in NTM disease should be investigated