Genotyping of mycobacterium tuberculosis with VNTR technique in Mianyang,Sichuan

Objective To discuss the genotyping of mycobacterium tuberculosis clinical isolates in Mianyang area by variable number tandem repeats(VNTRs) technique and provide scientific basis for the prevention and control of tuberculosis.Methods Mycobacterium tuberculosis clinical isolates were selected from Mianyang area,the polymorphism of VNTR locus was tested with PCR.The clustering of genotype was analyzed with BioNumerics 5.0.Results 15 VNTR loci of 79 mycobacterium tuberculosis clinical isolates were analyzed respectively.The results showed that there were obvious polymorphisms of VNTRs.The discrimination power of these loci appeared different from each other,with the biggest Hunter-Gaston index(0.880) loci was QUB-11b,the smallest one(0.234) loci was ETR C,HGI of 15-locus reached 1.The clustering of genotype showed that these strains could be categorized into 7 gene clusters and 79 genotypes,the proportions of cluster Ⅲ and cluster Ⅴ were the biggest,46.8% were cluster Ⅲ which including 37 strains and 41.8% were cluster Ⅴ which including 33 strains,other strains were of scattered distribution.Conclusions The results showed that there were obvious polymorphisms of VNTRs of mycobacterium tuberculosis clinical strains in Mianyang,most of the epidemic strains belonged to cluster Ⅲ and cluster Ⅴ.It is suggested that surveillance of these epidemic genotype should be strengthened.