Comparison of molecular epidemiology of Mycobacterium tuberculosis in parts of Xinjiang and Ganshu provinces

Objective To understand the difference on molecular epidemiology of Mycobacterium tuberculosis in parts of Xinjiang and Ganshu provinces. Methods Clinical isolates were collected from smear positive TB patients in 3 counties (district) in Xinjiang and Gansu from March to December in 2008. The patients' gender, ethnic group, disease history, drug resistant spectrum and sample source information were collected too. Drug susceptibility test was performed by using proportion method. Beijing genotype and sub-genotypes of M. tuberculosis were identified by using real time PCR. The phylogenetic tree of M. tuberculosis was constructed by using MIRU-VNTR method. Results Among 146 M. tuberculosis clinical isolates, eighty-four were Beijing/W lineage strains (57.5%), of which 66 were modern W strains/typical Beijing strains. The MIRU-VNTR typing results showed that there were 140 genotypes in 146 strains, including 134 unique genotypes and 6 cluster genotypes. Conclusion Beijing/W lineage strains were predominant in the strains sampled in Gansu, and most of them were modern W strains/typical Beijing strains, but non Beijing/W lineage strains were predominant in the strains sampled in Xinjiang. The difference on molecular epidemiology of M. tuberculosis between Xinjiang and Gansu was obvious.