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目的:通过调研黑龙江省部分重要的奶源地区春、夏季的原料奶,确定该地区原料奶中致泻性大肠杆菌的主要类型和相关毒力基因的存在情况。方法:在哈尔滨、绥化和大庆地区的27个奶牛场和奶牛养殖户采集原料奶,通用生化试验和血清学试验,分离鉴定原料奶中的致泻性大肠杆菌并确定相应的血清型。采用多重PCR方法分别检测EPEC和ETEC中eaeA与bfpA以及stⅠ与ltⅠ毒力基因的存在情况。结果:从81份原料奶样品中分离、鉴定出致泻性大肠杆菌21株(检出率22.22%),其中EPEC8株、ETEC10株和EIEC3株。经多重PCR检测8株EPEC和10株ETEC,确定它们分别含有eaeA与bfpA以及stⅠ与ltⅠ毒力基因。结论:黑龙江省部分重要奶源地区的原料奶均不同程度地被污染了致泻性大肠杆菌,尤以ETEC和EPEC两种类型居多;分离出的ETEC和EPEC分别含有stⅠ与ltⅠ以及eaeA与bfpA毒力基因。
Objective: To investigate the main types of diarrheogenic Escherichia coli in raw milk and the existence of related virulence genes in raw milk from some important milk source areas in spring and summer in Heilongjiang Province. Methods: Raw milk, common biochemical tests and serological tests were collected from 27 dairy farms and dairy cattle farms in Harbin, Suihua and Daqing, and the diarrheogenic Escherichia coli in raw milk was isolated and identified and the corresponding serotypes were determined. Multiplex PCR was used to detect the presence of eaeA, bfpA, and stI and ltI virulence genes in EPEC and ETEC, respectively. Results: 21 strains of diarrheogenic E.coli (22.22%) were isolated and identified from 81 raw milk samples, including EPEC8, ETEC10 and EIEC3. Eight EPECs and 10 ETECs were detected by multiplex PCR, and they were confirmed to contain eaeA and bfpA and stI and ltI virulence genes, respectively. Conclusion: The raw milk of some important milk sources in Heilongjiang Province are polluted diarrhea-causing Escherichia coli to some extent, especially in the two types of ETEC and EPEC. The isolated ETEC and EPEC contain stⅠ and ltⅠ and eaeA and bfpA Virulence genes.