Genotyping and drug resistance patterns of Mycobacterium tuberculosis strains in five provinces of China

Abstract

Objective: To evaluate the distribution of the Mycobacterium tuberculosis Beijing genotype and the association of the genotype with drug-resistant M. tuberculosis strains in five provinces in China.

Design: M. tuberculosis strains (n = 158) isolated from five provinces of China were subjected to insertion sequence 6110 restriction fragment length polymorphism (RFLP), spoligotyping and mycobacterial interspersed repetitive units (MIRU) analyses. The prevalence of the Beijing genotype strains in each province was determined and compared. The proportion method was used to test the drug susceptibility of all strains.

Result: Of the 158 strains, 123 (77.8%) were identified as the Beijing genotype by RFLP and spoligotyping. Nearly all the strains (n = 152, 96.2%) were grouped into 14 shared spoligotypes. Six other spoligotypes were unique to China. The prevalence of the Beijing genotype was significantly higher in the interior than in coastal areas (P < 0.001, OR 5.4, 95%CI 2.3-12.7). Resistance to rifampicin (RMP) was associated with the Beijing strain (P = 0.05, OR 3.7, 95%CI 1.2-11.1).

Conclusion: The M. tuberculosis Beijing genotype varies in prevalence in different regions of China and is solely associated with RMP resistance.