Increasing Prevalence Rate of Nontuberculous Mycobacteria Infections in Five States, 2008-2013

Many nontuberculous mycobacteria (NTM) are clinically significant pathogens that cause disease in a variety of different human organs and tissues. A population-based study was undertaken to investigate the prevalence of patients with a positive specimen for NTM within five states of the United States. We determined the case and age distribution of patients with at least one specimen positive for NTM, using data submitted to the disease surveillance systems of five states (Maryland, Mississippi, Missouri, Ohio, and Wisconsin) between 2008 and 2013. Crude, age-specific, and age-adjusted prevalence rates per 100,000 persons were calculated for each state. From 2008 to 2013, a total of 24,226 NTM cases were reported to the disease surveillance systems of the five states. The overall average annual age-adjusted prevalence rate rose from 8.7 to 13.9 per 100,000 persons between the beginning and end of the surveillance period. The number of cases and case rate in the 50-80+-year age group was higher than in the 0-49-year age group. Prevalence by age category differed among the five states. The highest number of NTM cases was observed in Mississippi for the 80+-year age group, whereas Wisconsin observed the highest number of NTM cases in the 60- to 69-year age group. From 2008 to 2013, the number of patients with positive specimens for NTM rose. This trend is likely to continue in the coming decade as the U.S. population ages. To reduce the prevalence of NTM infections, medical guidance for susceptible populations is needed regarding actions that can be taken to avoid sources and routes of exposure to NTMs if the disease burden is to be reduced.