Revisiting John Snow to Meet the Challenge of Nontuberculous Mycobacterial Lung Disease

Abstract

Nontuberculous mycobacteria (NTM) are ubiquitous components of the soil and surface water microbiome. Disparities by sex, age, and geography demonstrate that both host and environmental factors are key determinants of NTM disease in populations, which predominates in the form of chronic pulmonary disease. As the incidence of NTM pulmonary disease rises across the United States, it becomes increasingly evident that addressing this emerging human health issue requires a bold, multi-disciplinary research framework that incorporates host risk factors for NTM pulmonary disease alongside the determinants of NTM residence in the environment. Such a framework should include the assessment of environmental characteristics promoting NTM growth in soil and surface water, detailed evaluations of water distribution systems, direct sampling of water sources for NTM contamination and species diversity, and studies of host and bacterial factors involved in NTM pathogenesis. This comprehensive approach can identify intervention points to interrupt the transmission of pathogenic NTM species from the environment to the susceptible host and to reduce NTM pulmonary disease incidence.

Keywords: geographic distribution; mycobacterial infections; opportunistic plumbing pathogens; surface water.

Figure 1

Geographic variability across the United States in the percent of very poorly-drained soil. Data from the United States Department of Agriculture USDA), National Resources Conservation Service (NCRS); reproduced with permission from the Biota of North America Program.

Figure 2

Geographic variability in evapotranspiration levels in the United States, 1971–2000; reproduced with permission from Sandford et al., 2012.

Figure 3

Age-adjusted standardized mortality rate from chronic obstructive pulmonary disease in the United States, 2014; reproduced with permission from Dwyer-Lindgren et al., 2017.

Figure 4

Significant clusters of counties identified as being at high or low risk for pulmonary NTM disease among U.S. Medicare beneficiaries 65 years of age and older; reproduced with permission from Adjemian et al., 2012.