数目可变串联重复序列分子指纹分型法鉴定北京基因型结核分枝杆菌

Identification of Mycobacterium tuberculosis strains of Beijing genotype with variable number of tandem figerprinting typing

目的探讨数目可变串联重复序列(VNTR)分子指纹分型法在北京基因型结核分枝杆菌菌株识别中的价值,并与间隔区寡核苷酸分型(Spoligoty-ping)法进行比较。方法对50株临床结核分枝杆菌行核酸抽提后,以12个VN-TR位点引物分别扩增,对所得的指纹图谱进行分析,并与Spoligotyping结果比较。结果本研究中采用的12个VNTR位点均具有多态性。Spoligotyping分型有88%(44/50)菌株为北京基因型。相同Spoligotyping基因型的43株菌用VN-TR可分为24种基因型。VNTR的各个多态性位点中对北京基因型菌株辨别力最高的是MIRU26位点。结论 VNTR可作为结核分枝杆菌分子流行病学调查的初筛方法,结合Spoligotyping可进行北京基因型菌株的识别。

Objective To explore the value of variable number of tandem repeats（VNTR）fingerprinting typing in the recognition of Beiijng genotype Mycobacterium tuberculosis and compare the genotype with traditional Spoligotyping.MethodsDNA of 50 clinical Mycobacterium tuberculosis strains were amplified by 12 pairs of primers corresponding to 12 VNTR sites and genotypes,the results were compared with Spoligotyping.Results There were 88%（44/50）of MTB strains in this research were Beijing genotype with Spoligotyping.All of 12 VNTR locus were polymorphic and the repeated copy numbers varying from 2 to 7.Fifty strains were divided into 29 groups by VNTR,22 groups of which contain only one unique strain,another 7 groups contained two or more than two strains called ＂cluster＂ which standed for epidemically related strains.The biggest cluster contained 16 strains.MIRU26 was the most polymorphic for Beijing strains,the Polymorphic Index（PI）was 0.390.All of 43 Beijing strains with the same spoligotyping genotype could be further divided into 24 different groups.Conclusions Characterized by easy,rapid and may be standardized,VNTR can be used as the screening method for molecular epidemiology of Mycobacterium tuberculosis and could identify Beijing genotype strains if combined with Spoligotyping.