多位点串联重复序列分析和脉冲场凝胶电泳对伤寒沙门菌基因分型

Comparative evaluation of multilocus variable-number tandem-repeat analysis and pulsed-field gel electrophoresis for genotyping Salmonella enterica serovar Typhi isolates

目的：比较多位点串联重复序列分析（ MLVA）和脉冲场凝胶电泳（ PFGE）对伤寒沙门菌基因分型的能力，构建适合伤寒沙门菌的MLVA分型方法。方法根据国外文献报道选出5个多变的伤寒沙门菌串联重复序列（ VNTR）位点（ SAL02、SAL11、SAL16、SAL20、TR4699）设计MLVA分型方案，运用MLVA分型方案和国际PulseNet公布的沙门菌PFGE分型方案对2002至2007年21株流行病学不相关的深圳社区感染伤寒沙门菌基因分型，比较这两种分型方法对伤寒沙门菌基因分型的能力。结果5个单一VNTR位点对深圳地区伤寒沙门菌的分型能力（ D值）为0.838～0.943；使用MLVA分型方法，获得19种MLVA型别；使用PFGE分型方法，获得19种PFGE型别；两种分型方法的D值均为0.99，且结果完全一致。结论5个VNTR位点的MLVA分型方法可作为一种简单快速准确的基因分型方法用于伤寒沙门菌感染流行的分析。

Objective To evaluate the capability of multilocus variable-number tandem-repeat （VNTR） analysis （MLVA） and pulsed-field gel electrophoresis （PFGE） for genotyping Salmonella enterica serovar Typhi （ S. Typhi） isolates. Methods Five polymorphic VNTRs （ SAL02, SAL11, SAL16, SAL20, and TR4699 ） that were observed in S. Typhi strains from previous studies were selected to establish MLVA. Twenty-one epidemiologically unrelated S. Typhi strains that were isolated from Shenzhen, China from 2002 to 2007 were genotyped by the established MLVA, and the results were compared with those by PFGE. Results The Simpson＇s index of diversity （D value） for all five different VNTRs ranged from 0. 838 to 0. 943. A total of 19 MLVA profiles and 19 PFGE profiles were found, respectively. The D value for both MLVA and PFGE were 0. 99 and the test results from two analyses were identical. Conclusion The five polymorphie VNTRs analysis could be used as an alternative typing scheme for epidemiologic investigation of S. Typhi infection.