市售鲜鸡蛋中沙门氏菌的分离鉴定及毒力岛基因检测

目的:监测市售鲜鸡蛋中沙门氏菌的污染情况,检测分离菌株的致病性及其毒力岛基因携带情况,了解沙门氏菌分离株毒力岛基因的携带与其致病力的相关性。方法:从陕西省不同地市的超市中随机购买鲜鸡蛋,无菌取其蛋壳膜分离沙门氏菌,聚合酶链式反应方法扩增沙门氏菌菌属特异性invA基因鉴定分离株;对分离菌株进行无特定病原体(SPF)雏鸡的致病性试验,依据GenBank发表的基因序列,设计引物聚合酶链式反应检测沙门氏菌毒力岛(SPI)核心蛋白基因。结果:从陕西省55家超市1100枚鲜蛋中分离鉴定出30株沙门氏菌,分离率达2.73%;动物致病性实验表明,30株沙门氏菌中13株有致病力,其中强致病力菌株有7株,占23.3%;分离菌株的毒力岛基因携带率分别为:SPI-1 60%、SPI-2 73.3%、SPI-3 100%、SPI-4 90%、SPI-5 76.7%,毒力岛基因SPI-1+SPI-2的携带与细菌致病性有关。结论:市售鲜鸡蛋中沙门氏菌携带率为2.73%,分离菌株对动物具有一定的致病力,毒力岛基因SPI-1+SPI-2的携带与沙门氏菌的致病性呈正相关。

Isolation,Identification and Pathogenicity Island Gene Detection of Salmonella in Commercial Eggs

Objective: To monitor the Salmonella contamination status of commercial eggs,detect the pathogenesis and pathogenicity island(SPI) gene of Salmonella isolates and their correlation.Methods: Commercial eggs were collected from supermarkets in different cities in Shaanxi province.The eggshell membranes were harvested for isolating and culturing Salmonella in eggs.The strain isolates were identified through the PCR amplification of the special gene invA from Salmonella.The isolated strains were used for testing the pathogenesis for chicken.According to the sequence of SPI genes published in GenBank,PCR primers were designed to amplify and identify the SPI genes of core proteins.Results: A total of 30 Salmonella strains were isolated from 1100 commercial eggs that were purchased from 55 supermarkets.According to animal pathogenesis tests,13 strains were pathogenic and 7 strains were strongly pathogenic among these Salmonella strains.The carrying rate of SPI gene was 60% for SPI-1,73.3% for SPI-2,100% for SPI-3,90% for SPI-4 and 76.7% for SPI-5.Meanwhile,SPI-1 and SPI-2 revealed an obvious correlation with pathogenesis.Conclusion: The isolation rate of Salmonella from commercial eggs observed in this study is 2.73%.SPI-1 and SPI-2 have a positive correlation with pathogenesis.