Evolution of Mycobacterium tuberculosis Population Structure in Arkansas, 2009–2022, and Its Public Health Implications

The evolution of the Mycobacterium tuberculosis (M.tb) population structure in each population over time can help elucidate the drivers of tuberculosis (TB) epidemics. However, few previous studies have examined recent changes in M.tb population structure in low-incidence settings where TB elimination remains challenging. To fill this knowledge gap, we conducted a time-trend ecological study using deidentified TB surveillance and M.tb spoligotyping data on 696 incident TB cases diagnosed in Arkansas during 2009–2022. We calculated the yearly proportions of cases attributable to each of the major genetic lineages circulating in the state from 2009 to 2022 and assessed the association of M.tb genetic lineages with clinical characteristics using logistic regression models. The East Asian lineage contributed to 11.8% (7/60) of the cases in 2009, but this proportion increased to 30.2% (13/43) in 2022. Similarly, the proportion of the analyzed pulmonary TB (PTB) cases caused by the East Asian lineage increased from 14% (7/50) in 2009 to 30.5% (11/36) in 2022. The remarkable expansion of the East Asian lineage and the significant decline of the Euro-American lineage in Arkansas over time have important implications for TB elimination in the state.