关键词: 分枝杆菌, 结核, 基因型, 小卫星重复

Abstract: Objective  To investigate the genotype distribution of Mycobacterium tuberculosis clinical isolates from Anhui province with the multiple-locus variable number tandem repeats analysis (MLVA).  Methods  391 M. tuberculosis clinical isolates randomly selected from Anhui province were cultured in Lowenstein-lensen medium. The bacteria were collected, and then their genome DNAs were extracted. The polymorphism of 15 VNTR locus in the DNA samples was analyzed by PCR respectively. The clustering of genotype was analyzed with the software BioNumerics(Version 5.0). Chi-square test was used for statistical analysis.  Results  The clustering analyses of genotype showed that 391 strains were categorized into 4 gene clusters (genogroup Ⅰ, Ⅱ, Ⅲ and Ⅳ), in which 3.32%（13/391）was belong to genogroup Ⅰ,  3.07%（12/391）was genogroup Ⅱ, 89.00%（348/391） was genogroup Ⅲ, and 4.60%（18/391）was genogroup Ⅳ. The 391 strains were typed to 183 distinct MIRU patterns. 149 isolates were unique, 242 strains were grouped into 34 diferent MIRU clusters, in which the largest cluster was genotype 424343357333544 and included 64 strains．There were obvious polymorphisms of VNTRs in these strains,Mtub21 and MIRU26 were highly discriminative (h=0.591 and 0.527, respectively)， ETR-B, ETR-C, ETR-D and MIRU23 were poorly discriminative (h=0.125, 0.08, 0.124 and 0.137, respectively)．Distribution of genotypes was not significantly associated with the resistance to four drugs (the values of χ² were 0.22, 0.00, 0.01, 0.07 respectively，P>0.05).  Conclusion  M. tuberculosis clinical strains from Anhui province had obvious VNTR polymorphisms. There were at least 4 clusters of VNTR genotypes, and cluster type Ⅲ was predominant. The surveillance on this type of M. tuberculosis needs to be strengthened.

Key words: Mycobacterium tuberculosis, Genotype, Minisatellite repeats