LAUSR

RATIONALE Population-based data on the epidemiology of nontuberculosis mycobacterial (NTM) infections are limited, particularly with respect to variation in NTM infection amongst racial groups and socioeconomic strata. Wisconsin is one of a handful of states in which mycobacterial disease is notifiable, allowing for large, population-based analyses of the epidemiology of NTM infection in this state. OBJECTIVES To estimate the incidence of NTM infection in Wisconsin adults, describe the geographic distribution of NTM infection across the state, identify the frequency and type of infection caused by different NTM species, and investigate associations between NTM infection and demographics and socio-economic status. METHODS We conducted a retrospective cohort study using laboratory reports of all NTM isolates from Wisconsin residents submitted to the Wisconsin Electronic Disease Surveillance System (WEDSS) during 2011 to 2018. For the analyses of NTM frequency, multiple reports from the same individual were enumerated as separate isolates when non-identical, collected from different sites, or collected more than one year apart. RESULTS A total of 8,135 NTM isolates from 6,811 adults were analyzed. M. avium complex (MAC) accounted for 76.4% of respiratory isolates. M. chelonae-abscessus group was the most common species isolated from skin and soft tissue. The annual incidence of NTM infection was stable over the study period (22.1/100,000 to 22.4/100,000). Cumulative incidence of NTM infection in Blacks (224/100,000) and Asians (244/100,000) was significantly higher compared to their white counterparts (97/100,000). Total NTM infections were significantly more frequent (p<0.001) in individuals from disadvantaged neighborhoods, and racial disparities in incidence of NTM infection generally remained consistent when stratified by measures of neighborhood disadvantage. CONCLUSIONS Over 90% of NTM infections were from respiratory sites, with the vast majority caused by MAC. Rapidly growing mycobacteria predominated as skin and soft tissue pathogens and were important minor respiratory pathogens. We found a stable annual incidence of NTM infection in Wisconsin between 2011 and 2018. NTM infection, occurred more frequently in non-white racial groups and in individuals experiencing social disadvantage, suggesting NTM disease may be more frequent in these groups as well.