Analysis on the Genotyping of 71 Mycobacterium Tuberculosis Clinical Strains Isolated from Zhejiang Province with MLVA

Objective To investigate the genotyping and distribution pattern of the variable number tandem repeats (VNTR)of Mycobacterium tuberculosis clinincal isolates in Zhejiang province with Multiple-locus VNTR analysis(MLVA)pre- liminarily.Methods M.tuberculosis clinical isolates selected from Zhejiang province randomly were cultured with Lowenstein -Jensen medium.The bacteria from which the genome DNA was extracted were collected.The polymorphism of VNTR locus was tested in the DNA samples with PCR respectively.The clustering of genotype was analyzed with BioNumerics(Version 5.0). Chi-square test was used for statistical analysis.Results 15 VNTR loci of 71 M.tuberculosis clinical isolates were analyzd respectively.The results showed that there were obvious polymorphisms of VNTRs.The clustering of genotype showed that these strains could be categorized into 4 gene clusters(Ⅰ,Ⅱ,Ⅲ,Ⅳ)and 58 genotypes.8.5% were clusterⅠincluding 5 geno- types,18.3% were clusterⅡincluding 13 genotypes,70.4% were clusterⅢincluding 38 genotypes,and 2.8% were clusterⅣincluding 2 genotypes.Conclusion The results showed that there were obvious polymorphisms of VNTRs of M.tuberculosis cilinical strains preliminarily.There were at least 4 clusters of VNTR genotype and clusterⅢwas the predominant prevalent strain in Zhejiang province.