Combining molecular typing and spatial pattern analysis to identify areas of high tuberculosis transmission in a moderate-incidence county in Taiwan

In total, 303 randomly selected clinical Mycobacterium tuberculosis (MTB) isolates from 303 patients (collected January to December 2012) in central Taiwan were examined. The major lineages found were Beijing (N = 114, 37.62%), Haarlem (N = 76, 25.08%) and East African–Indian (EAI) (N = 42, 13.86%). Notably, younger persons (≤30 years old) were 6.58 times more likely to be infected with a Beijing genotype compared to older persons (>70 years) (p < 0.05). Combining molecular typing methods and geographical information system (GIS) analysis, we uncovered a twofold higher incidence of Beijing strains in a hotspot area (33%) compared to non-hotspot areas (17%). By 24 MIRU-VNTR typing, persons in clustered groups were 1.96 times more likely to be infected with a Beijing strain compared with non-clustered persons, suggesting recent spread and emergence of MTB. Finally, we observed a trend in which TB incidence increased as the density/concentration of analyzed environmental factors increased, suggesting that environmental factors are associated with TB transmission; however, only population density was found to be significantly associated with increased risk of TB (p < 0.05). Molecular typing methods combined with spatial analysis suggest possible TB transmission. Early intervention to interrupt transmission may be most effective if targeted to hot zones of TB.