中文摘要：

本研究旨在了解产超广谱β-内酰胺酶（ESBLs）大肠杆菌和CTX-M型耐药基因在食品动物的流行状况。对分离自养殖场的1273株大肠杆菌（健康动物源755株,患病动物源518株）,采用双纸片协同试验筛选ESBLs阳性菌,并通过PCR法和基因测序鉴定阳性菌CTX-M型的基因型。1273株食品动物源大肠杆菌中筛选出产ESBLs阳性菌181株,阳性率为14.2%,其中患病动物阳性率比健康动物高,分别为19.9%和10.3%。151株（83.4%）产ESBLs大肠杆菌中检测到CTX-M型基因,占所有食品动物源大肠杆菌的11.8%,其中以CTX-M-9G为主,阳性率为79.5%（120/151）,远高于CTX-M-1G的携带率25.8%（39/151）,其中8株同时携带了CTX-M-1G和CTX-M-9G。产ESBLs的大肠杆菌在食品源动物中流行普遍,CTX-M是产ESBLs阳性菌中的主要流行基因型。

英文摘要：

The purpose of this study was to investigate the prevalence of extended-spectrum β-lactamase（ESBLs） and CTX-M genes among Escherichia coli isolated from food-producing animals.A total of 1273 E.coli（755 from healthy animals and 518 from sick animals） isolated from food-producing animals,including pigs,chickens and ducks.ESBLs-producing isolates were screened by the double-disk synergy test.PCR was performed to amplify CTX-M genes among ESBL-producing isolates.ESBLs production was detected by the screening method for 181（14.2%） of the 1273 isolates.The percentage of ESBLs production in isolates from sick animals（19.9%） was higher than isolates from healthy animals（10.3%）.In 181 ESBLs-producing strains,151 isolates（83.4%）,representing 11.8% of the total E.coli isolates,harbored the CTX-M type β-lactamases.High prevalence of ESBL and CTM-M genes were found in E.coli isolates from food-producing animals.CTX-M genes were the main type of ESBLs in E.coli isolates from food-producing animals.