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目的比较脉冲场凝胶电泳(PFGE)和多位点串联重复序列分析(MLVA)分型方法用于我国肠炎沙门菌分子分型的能力,建立我国肠炎沙门菌MLVA分型标准操作方法及数据库。方法根据国际PulseNet公布的肠炎沙门菌PFGE和MLVA分型方案,对来自我国6个省(直辖市)的289株肠炎沙门菌进行分子分型分析,并结合流行病学资料,评价这两种分型方法对我国肠炎沙门菌分离株的分型能力。结果 289株肠炎沙门菌经XbaⅠ酶切,PFGE后获得55种带型,其分辨能力(D值)为0.8433。PFGE优势带型为JEGX01.CN0003及JEGX01.CN0001,带型频率分别为35.6%、25.6%,但二者仅表现两个条带的差异,其余型别均低于5%。采用MLVA分析,获得63种型别,分为2个群,D值为0.8608,说明MLVA分辨能力高于单酶切PFGE,但分型能力仍然有限。MLVA主要型别ST1包含了97株菌株,占37.5%,分布于各省及各年份。若联合PFGE及MLVA分型,则产生104种型别,D值为0.9058。对流行病学调查显示为肠炎沙门菌暴发病例菌株进行PFGE双酶切及MLVA分型,结果均显示这些菌株具有明显的聚集性,但不能与同期散发菌株完全区分开。结论 MLVA与PFGE分型方法的分辨能力在肠炎沙门菌中较低,在确认肠炎沙门菌引起的暴发事件时,需紧密结合流行病学调查资料,采用双酶切PFGE或MLVA进行分型分析。
Objective To compare the molecular typing of Salmonella enteritidis in China with pulsed-field gel electrophoresis (PFGE) and multi-locus tandem repeat analysis (MLVA) typing methods and establish the standard operation method and database of Salmonella enteritidis MLVA in China. Methods According to the International PulseNet published Salmonella enteritidis PFGE and MLVA genotyping program, 289 strains of Enterobacter sapsatitis from 6 provinces (municipalities) in China were molecularly typed and analyzed according to epidemiological data Typing ability of Salmonella enteritidis isolates in China. Results 289 Salmonella enteritidis were digested with Xba Ⅰ, and 55 bands were obtained after PFGE. The discrimination ability (D value) was 0.8433. The dominant bands of PFGE were JEGX01.CN0003 and JEGX01.CN0001, with the band frequencies of 35.6% and 25.6%, respectively, but the difference between the two bands showed only two bands and the others were below 5%. Using MLVA analysis, 63 types were obtained and divided into 2 groups with a D value of 0.8608, indicating that MLVA resolution is higher than that of single digestion PFGE but the typing ability is still limited. The major MLVA type, ST1, contains 97 strains, accounting for 37.5% of the total, in all provinces and years. When combined with PFGE and MLVA genotypes, 104 genotypes were generated with a D value of 0.9058. The epidemiological investigation showed that the cases of outbreaks of Salmonella enteritidis by PFGE double digestion and MLVA typing, the results showed that these strains have obvious aggregation, but can not be completely separated with the same period distributed strains. Conclusions The discrimination ability of MLVA and PFGE typing method is low in Salmonella enteritidis. In confirming the outbreak caused by Salmonella enteritidis, the epidemiological investigation data should be closely combined with the double enzyme digestion PFGE or MLVA.