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目的比较脉冲场凝胶电泳(PFGE)和两种国际多位点串联重复序列分析(MLVA)分型方法用于我国鼠伤寒沙门菌分子分型的能力,并初步确定适用于我国鼠伤寒沙门菌MLVA分型中的VNTR位点。方法根据国际Pu lseNet公布的沙门菌PFGE分型方案、MLVA分型方案(包含7个VNTR位点,简称MLVA_PN)及欧洲食源性疾病监测网公布的鼠伤寒沙门菌MLVA分型方案(包含5个VNTR位点,简称MLVA_EU),对来自我国5个省(直辖市)的175株鼠伤寒沙门菌进行分子分型分析,并结合流行病学资料,评价这三种分型方法对我国分离的鼠伤寒沙门菌的分型能力。结果 175株鼠伤寒沙门菌经XbaⅠ酶切,PFGE后,获得56种带型,其分辨能力(D值)为0.8823。对其中的主优势带型JPXX01.CN0001菌株55株进一步用第二种内切酶BlnⅠ酶切后,获得6种带型。用MLVA_EU分型,获得96种型别,D值为0.9758。应用MLVA_PN分析,获得98种型别,D值为0.9763。两种MLVA分型方法对菌株的分辨能力几乎相同,且分型结果具有较高的一致性。对流行病学调查显示为鼠伤寒沙门菌暴发患者和食物来源的菌株进行PFGE双酶切及MLVA分型,三种分型方法获得一致性结果,均显示这些菌株具有明显的聚集性。结论两种MLVA分型方法的分辨能力均高于PFGE,在确认鼠伤寒沙门菌引起的暴发事件时,采用需时较短,操作更方便的5个VNTR位点的MLVA分型方法可满足菌株聚集性分析。
Objective To compare the molecular typing of Salmonella typhimurium in China with pulsed-field gel electrophoresis (PFGE) and two international MLVA genotyping methods, and to determine the potential of Salmonella typhimurium VNTR locus in MLVA typing. Methods According to the Salmonella PFGE genotyping program published by Pu lseNet, the MLVA genotyping program (including 7 VNTR loci, MLVA_PN for short) and the MLVA genotyping program of Salmonella typhimurium released by the European Foodborne Disease Surveillance Network (including 5 A VNTR locus, referred to as MLVA_EU), molecular typing analysis of 175 S. typhimurium strains from 5 provinces in China and epidemiological data were used to evaluate the effects of these three typing methods on the isolation of rat Salmonella typhi typing ability. Results 175 Salmonella typhimurium strains were digested with Xba Ⅰ, and 56 bands were obtained after PFGE. Their resolving power (D value) was 0.8823. Among them, 55 isolates of the dominant dominant strain JPXX01.CN0001 were further digested with the second endonuclease Bln I to obtain 6 bands. With MLVA_EU typing, 96 types were obtained with a D value of 0.9758. With MLVA_PN analysis, 98 types were obtained with a D value of 0.9763. The two MLVA typing methods were almost identical to the strains and the typing results were highly consistent. Epidemiological survey showed that patients with outbreak of Salmonella typhimurium and food-derived strains were double-PFGE digestion and MLVA typing, three types of methods to obtain consistent results showed that these strains have obvious aggregation. Conclusion Both MLVA genotyping methods are superior to PFGE in discriminating ability. When confirming the outbreak of Salmonella typhimurium, the MLVA genotyping method of five VNTR loci that needs shorter time and more convenient operation can meet the requirement of strain Aggregation analysis.