肠炎沙门菌可变数目串联重复序列位点用于多位点可变数目串联重复序列分型分析的评价

Assessment of the application of variable-number tandem repeat loci of Salmonella Enteritidis in subtyping multiple-locus variable-number tandem repeat analysis

目的 评价不同肠炎沙门菌可变数目串联重复序列（VNTR）位点用于多位点可变数目串联重复序列（MLVA）分型的可行性.方法 选取已报道使用的肠炎沙门菌11个VNTR位点,对中国不同时间和地区分离的16株菌进行初步评价,选取具有单一扩增条带的位点进行104株肠炎沙门茵的MLVA分型分析.对这些菌株同时进行脉冲场凝胶电泳（PFGE）分析,比较MLVA分型方法与PFGE分型方法对菌株分型能力的强弱.结果 初筛得到7个VNTR位点用于扩大菌株的分析,这些位点将104株菌分为16个MLVA型别,D值为0.7222,这些菌株同时被分为22个PFGE型别,D值为0.7974.对两种方法各自所分的最大组包含的菌株进行比较,发现PFGE具有更强的分辨能力;从频数分布看,PFGE方法分型结果比较分散,MLVA分型较为集中.结论 用于国际肠炎沙门菌分型具有扩增多态性的VNTR位点在国内分离株中并不都具有多态性结果,在MLVA方法学建立中应选择更多的VNTR位点进行广泛的筛选才有利于国际实验室间的方法的统一.

Objective To evaluate the feasibility of the application of variable-number tandem repeat（VNTR）loci of Salmonella Enteritidis（S. enteritidis）in subtyping mutiple-locus variable-number tandem repeat analysis（MLVA）.Methods A total of 16 isolates of S.enteritidis from different place and time in China were preliminarily assessed by choosing 11 reported VNTR loci.the loci with single amplified bands were picked to subtype all 104 S.enteritidis isolates.The isolates were also analyzed by pulse field gel electrophoresis（PFGE）to compare the superiority or inferiority of MLVA method and PFGE method.Results Seven VNTR loci were selected from the preliminary screening to expand the analysis,and the 7 VNTR loci had grouped 104 of S.enteritidis isolates into either 16 MLVA subtypes or 22 PFGE subtypes.with the D value at 0.7222 and 0.7974,respectively.Comparing with the isolates in MLVA subtypes.the isolates in PFGE showed a stronger resolving power.Meanwhile the results in PFGE showed a more disperse frequency distribution than those in MLVA.Conclusion These results indicate that some VNTR locus which have shown a good polymorphism intemationaUy,may fail to show polymorphism in China.thereby.more VNTR loci should be included in MLVA and the wide screening may benefit the unity of global laboratorial methods.