Molecular typing of multidrug-resistant mycobacterium tuberculosis based on DTM-PCR, MIRU-VNTR, and sequencing of drug-resistance-associated genes in Wuhan / 公共卫生与预防医学

ABSTRACT

Objective To determine the genotype and clustering characteristics of multidrug-resistant (MDR) mycobacterium tuberculosis in Wuhan City. Methods A total of 149 mycobacterium tuberculosis strains from MDR tuberculosis (MDR-TB) patients were genotyped by DTM-PCR, mycobacterial interspersed repetitive unit–variable number tandem repeat typing (MIRU-VNTR) and sequencing of drug-resistant associated genes. The Hunter-Gaston discriminatory index (HGDI), clustering rate and recent minimum estimated infection rate were calculated. Results The cumulative HGDI of all MIRU loci was 0.9944. Gene locus with the highest HGDI（0.6467）was QUB11b. Combing MIRU-VNTR and DTM-PCR, 111 unique genotypes and 11 clustered genotypes（38 strains）from 149 isolates were identified. The clustering rate was 25.50%, and the recent minimum infection rate was estimated to be 18.12%. After further genotyping by sequencing of drug-resistant associated genes, the results showed that 17 (44.74%) strains in each cluster shared the same mutation sites, while the other strains had different mutation sites. Conclusion The combination of DTM-PCR, 24 locus MIRU-VNTR typing and drug resistance gene sequencing demonstrates a relatively high discriminatory power, which is suitable for the genotyping of multi drug resistant mycobacterium tuberculosis in Wuhan. The epidemic of MDR-TB in Wuhan is mainly caused by reactivation, and the recent transmission rate is not high.