Preliminary study on the molecular epidemiology of mycobacterium tuberculosis strains from Guizhou in Western China

Objective To analyze the molecular characteristics and estimate the transmission of mycobacterium tuberculosis in the crowd. Methods M. tuberculosis strains were isolated from pulmonary tuberculosis patients in four countries, where the pulmonary tuberculosis report incidence rates were higher than the rest of the province. The strains were analyzed with the deletion of region of difference 105 and mycobacterial interspersed repetitive-unitvariable-number tandem-repeat (MIRU-VNTR) methods. Results Of 273 strains, 49.1% were identified to be Beijing family isolates, and all strains were typed into 262 MIRU-VNTR genotypes, of which 251 strains (91.9%) were unique genotypes and the remaining 22 strains (8.1%) were typed into 11 genotypes. The clustering rate was 8.1%. Conclusions It is the first time to apply 15 MIRU-VNTR loci to genotype the M. tuberculosis strains of Guizhou Province. The results suggest that the strains are highly polymorphic and 8.1% of patients are due to the recent transmission.