科研動態(tài)

為了解我國不同地區(qū)屠宰生豬肉品中致瀉性大腸桿菌污染情況及系統(tǒng)進化關(guān)系，降低由其帶來的公共衛(wèi)生危害，將近幾年分離自華北、華東、華中及西南地區(qū)豬屠體表面的283株大腸桿菌進行了致瀉性大腸桿菌多重PCR鑒定及2b-RAD測序分型。多重PCR鑒定結(jié)果顯示，共檢出36株致瀉性大腸桿菌，檢出率為12.7%，其中西南地區(qū)檢出率（26.92%）高于華北（13.33%）、華東（10.57%）和華中（10.81%）地區(qū)；5種致瀉類型中，產(chǎn)腸毒素大腸桿菌（ETEC）、腸致瀉性大腸桿菌（EPEC）、腸聚集性大腸桿菌（EAEC）、腸出血性大腸桿菌（EHEC）和腸侵襲性大腸桿菌（EIEC）的占比分別為33.33%、30.56%、25.00%、5.56%和5.56%。將致瀉性大腸桿菌進行2b-RAD測序，種群聚類分析顯示，這36株致瀉菌可分為8個亞群；系統(tǒng)發(fā)生樹分析顯示，親緣關(guān)系較近菌株的致瀉類型基本一致，分離時間也比較接近，而且來自同一地區(qū)菌株的親緣關(guān)系相對較近。可見，我國屠宰生豬肉品中污染的致瀉性大腸桿菌以ETEC、EPEC和EAEC類型為主，其流行分布有一定的地域差異，且其親緣關(guān)系呈一定的時空特異性。本研究為精準防控生豬屠宰環(huán)節(jié)致瀉性大腸桿菌污染，保障肉品衛(wèi)生安全提供了科學數(shù)據(jù)和技術(shù)支撐。

Multiplex PCR Identification and 2b-RAD Sequence Analysis of Porcine Diarrheagenic Escherichia coli in Different Regions in China

In order to make clear the status of contamination and phylogenetic relationship of diarrheagenic Escherichia coli（E.coli）in raw pork products in different regions of China and to reduce the public health hazards that might occur therefrom，diarrheagenic E.coli strains were identified by multiplex PCR from 283 E.coli strains isolated from the surface of pig carcasses in North China，East China，Central China and Southwest China in recent years，then 2b-RAD sequencing and gene typing were carried out. It was found that，by multiplex PCR，36 strains of diarrheagenic E.coli were detected out，with the detection rate of 12.7%，among which，the detection rate in Southwest China（26.92%）was significantly higher than those in North China（13.33%），East China（10.57%）and Central China（10.81%）；for the five types of diarrhea，enterotoxigenic E.coli（ETEC），enteropathogenic E.coli（EPEC），enteroaggregative E.coli（EAEC），enterohemorrhagic E.coli（EHEC）and enteroinvasive E.coli（EIEC）accounted for 33.33%，30.56%，25.00%，5.56% and 5.56%，respectively. After 2b-RAD sequencing for species clustering analysis，it was found that the 36 strains could be classified into 8 subgroups；it was shown that，by phylogenetic tree analysis，the strains with close genetic relationship belonged to similar diarrheagenic types，and their isolation time was also close，in particular，the strains from the same region were with closely genetic relationship. It was concluded that the diarrheagenic E.coli contaminated in raw pork products mainly included three types of ETEC，EPEC and EAEC，the diarrheagenic E.coli strains were distributed with regional diversity，and their genetic relationships were with certain spatial and temporal specificity. In conclusion，some scientific data and technical support were provided to prevent and control the containment with diarrheagenic E.coli during the process of pig slaughtering and to safeguard hygiene and safety of pork products.

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