13个VNTR位点用于113株结核分支杆菌的基因分型研究

目的 应用数目可变串联重复序列（VNTR）分子分型技术，对北京地区113株肺结核临床分离菌株进行分型研究，探讨北京地区菌株DNA多态性和基因型特征。方法 采用PCR和琼脂糖凝胶电泳技术对结核分支杆菌13个VNTR位点进行检测，并应用Gel-Pro analyzer 3．1软件和BioNumerics3．0软件进行结果分析。结果 113株结核分支杆菌可分为4个基因型（分别为Ⅰ、Ⅱ、Ⅳ和Ⅴ型），其中Ⅰ型占92．0％（104/113），其他3型所占比例很小，分别为Ⅱ型占4．4％（5／113），Ⅳ和Ⅴ型均为1．8％（2／113），而标准菌株H37Rv在分型中为独立的一个基因型，即Ⅲ型。结论 北京地区的结核分支杆菌存在基因多态性，其主要流行型为Ⅰ型。

Study on the genotyping of 113 Mycobacterium tuberculosis strains isolated in Beijing based on 13 variable number of tandem DNA repeats

Objective Variable Number of Tandem Repeats (VNTRs) analysis was a recently developed method which could serve as a 'real-time' genotyping tool for Mycobacterium tuberculosis. One hundred and thirteen M. tuberculosis isolates from the patients with tuberculosis in Beijing were analysed using the reference method to study the characters of genetic diversity and genotype. Methods Thirteen tandem repeat loci(ETR-A,ETR-C,ETR-D,MIRU10,MIRU16,MIRU27,MIRU31,MIRU40,Mtub21, Mtub30,Mtub38,Qub11a,Qub11b) in the total genome of MTB were analyzed by PCR and agarose gel electrophoresis method. The characters of the polymorphism of DNA fingerprinting of one hundred and thirteen MTB strains were analyzed with Gel-Pro analyzer 3.1 software and BioNumerics 3.0 software. Results One hundred and thirteen MTB strains were characterized and classified in to four genotype families(type I , type II , type IV , type V ) based on thirteen tandem repeat loci. One hundred and four isolates(92.0%) belonged to type I , the other three genotypes scattered, five strains(4.4% ) remaining with type II , while type IV and type V having the same quantity 1.8% (2/113) . M. tuberculosis H37Rv belonged to a unattached genotype( type III ). Conclusion There was obvious length polymorphism in the M. tuberculosis isolates which implied that type I was the epidemic strain clusters in M. tuberculosis in Beijing. VNTRs analysis seemed to be a simple, rapid, sensitive and valuable tool for epidemiological studies of M. tuberculosis complex organisms.