浙江省猪源产肠毒素大肠杆菌分子流行病学调查  

Molecular epidemiological investigation of porcine enterotoxigenic Escherichia coli in Zhejiang Province

作　　者：陈怡洁 袁秀芳[2] 徐丽华[2] 余斌[2] 苏菲[2] 叶十一 卢碧凯 蒋利明 张晖 李军星[2] CHEN Yijie;YUAN Xiufang;XU Lihua;YU Bin;SU Fei;YE Shiyi;LU Bikai;JIANG Liming;ZHANG Hui;LI Junxing(College of Life Science and Technology,Foshan University,Guangdong 528231,China;Institute of Animal Husbandry and Veterinary Science,Zhejiang Academy of Agricultural Sciences,Hangzhou 310021,China;Taizhou Animal Disease Prevention and Control Center,Taizhou,Zhejiang 317700,China)

机构地区：[1]佛山科学技术学院生命科学与工程学院,广东佛山528231 [2]浙江省农业科学院畜牧兽医研究所,浙江杭州310021 [3]浙江省台州市动物疫病预防控制中心,浙江台州317700

出　　处：《中国兽医学报》2023年第8期1651-1657,1709,共8页Chinese Journal of Veterinary Science

基　　金：浙江省自然科学基金资助项目(LY21C180002);浙江省重点研发计划资助项目(2019C02052-3);台州市农业科技资助项目。

摘　　要：本研究旨在调查浙江省猪源产肠毒素性大肠杆菌的流行情况和毒力基因特征。采用标准细菌学方法对大肠杆菌进行分离,并用聚合酶链反应(PCR)方法检测大肠杆菌的毒力基因。2014-2021年共分离到137个携带ETEC黏附素或肠毒素基因的大肠杆菌菌株,其中禁抗后平均每年分离到的菌株数量是禁抗前的2倍。肠毒素基因检测结果表明,STb(129/137,94.2%)最常见,其次是STa(64/137,46.7%)和LT(62/137,45.3%);黏附素基因以F18(56/137,40.9%)最占优势,其次为K88(28/137,20.4%),未检测到K99和987P及F41等黏附素。上述137个临床分离株中共检测到16种不同的毒力因子模式,平均每8.6个菌株产生一种不同的毒力因子模式;其中39.4%的菌株仅携带肠毒素基因,检测不到经典的黏附素基因,而1.5%的菌株则与之相反。共有81株菌同时检测到肠毒素和黏附素基因,占检出总数的59.1%。在所有被检测的生长阶段,肠毒素STb均为检出率最高的肠毒素,且随着日龄增加检出率逐渐降低。黏附素F18随着仔猪日龄的增加检出率不断提高;K88黏附素在各个生长阶段均能检出,尤其在产房仔猪中检出率最高。口腔灌服不同毒力因子模式ETEC菌株对小鼠的致死率介于0~40%,攻毒7 d后不同组的小鼠肠内容物中攻毒菌株的带菌率介于0~100%。综上所述,饲料禁抗后浙江省腹泻猪群中ETEC分离率明显上升,所携带的肠毒素以STb为主,黏附素以F18为主。菌株的毒力因子模式复杂,对小鼠的致病力及在小鼠体内的持续存活能力有明显差异,说明小鼠作为猪源ETEC的传播媒介作用在不同菌株间存在较大差异。The present study was performed to investigate the prevalence and characteristics of some virulence genes of porcine enterotoxigenic Escherichia coli in Zhejiang Province.The standard bacteriological method was used to isolate and identify E.coli,and then polymerase chain reaction(PCR)was performed to determine virulence genes in E.coli.A total of 137 E.coli strains carrying ETEC adhesin or enterotoxin genes were isolated from 2014 to 2021,and the average number of isolates per year after the ban on antibiotics was twice that before the ban on antibiotics.The results of enterotoxin gene detection showed that STb(129/137,94.2%)was the most prevalent,followed by STa(64/137,46.7%)and LT(62/137,45.3%);for adhesin genes,F18(56/137,40.9%)was the most dominant,followed by K88(28/137,20.4%).Adhesins such as K99,987P,and F41were not detected.A total of 16different virulence gene profiles were detected in the above137clinical isolates,with an average of one different virulence gene profile per 8.6strains.Among them,39.4%of the isolates only carried enterotoxin genes and no classical adhesin gene was detected,while 1.5%of the isolates were the complete opposite.A total of 81strains were found with the presence of both enterotoxins and adhesin genes,accounting for 59.1%of the total isolates.STb was the enterotoxin with the highest detection rate in all the tested growth stages,and the detection rate gradually decreased with age.The detection rate of adhesin F18 increased with the increase of age;K88 adhesin could be detected in all growth stages,especially in the farrowing piglets.The lethal rate of ETEC strains in different virulence gene profiles administered orally to mice was between 0 and 40%,and the carrying rate of ETEC strains in intestinal contents of mice in different groups was between 0 and 100%after 7dof poisoning.In summary,the number of ETEC infection cases in Zhejiang Province increased significantly after the ban on the use of antibiotics in feed.The dominant enterotoxin and adhesin were STb and F18,respecti

关 键 词：产肠毒素性大肠杆菌(ETEC) 毒力因子 黏附素基因 肠毒素基因 分子流行病学 

分 类 号：S852.61[农业科学—基础兽医学]