中文摘要：

质粒介导的超广谱β-内酰胺酶（ESBLs）和AmpC酶广泛传播和扩散,导致全球范围内肠杆菌科细菌对超广谱头孢菌素类的耐药性发展迅速,引起人们高度重视。食品动物源大肠杆菌可作为耐药基因储库,对细菌耐药性在动物、环境和人之间的传播起着非常重要的作用。本研究从2009年患病的食品动物,包括鸡、鸭、鹅和猪,分离鉴定了315株大肠杆菌,调查ESBLs和AmpC酶在患病食品动物中的流行分布。经双纸片协同扩散实验筛选出61株ESBL阳性菌株,PCR检测共检测出8种blaCTX-M基因,分别为blaCTX-M-14/14b、blaCTX-M-79、blaCTX-M-65、blaCTX-M-27、blaCTX-M-15、blaCTX-M-24、blaCTX-M-98和blaCTX-M-13,其中检出率最高的为blaCTX-M-79,其次为blaCTX-M-14/14b。本研究还检测出1株新的SHV型酶,命名为SHV-135;PCR共检测出5株大肠杆菌携带质粒源CMY-型AmpC酶,其中2株鹅源大肠杆菌携带1个新型CMY酶,命名为CMY-64。本研究表明患病动物分离的大肠杆菌中ESBLs和AmpC酶存在复杂性和多样性,而且新型β-内酰胺酶检出日益增多,提示兽医临床应慎用β-内酰胺类抗生素。

英文摘要：

Extensive dissemination and spread of plasmid mediated extended spectrum β-lactamases（ESBLs） and AmpC-type β-lactamases resulted in a rapid development of resistance to extended spectrum cephalosporins in Enterobacteriaceae worldwide,causing globe concerns.Food-producing animal origin E.coli,as a resistant gene reserviors,plays an important role in resistance dissemination among animals,environment and human.The present study isolated and identified 315 E.coli from sick food-producing animals,including chickens,ducks,geese and pigs,investigated the prevalence of ESBLs and AmpC among sick food-producing animals.Sixty-one ESBLs positive E.coli were selected by double disc synergy test.Eight varieties blaCTX-M-type genes in total were detected,including blaCTX-M-14/14b、blaCTX-M-79、blaCTX-M-65、blaCTX-M-27、 blaCTX-M-15、blaCTX-M-24、blaCTX-M-98 and blaCTX-M-13.A novel SHV-type ESBLs was identified and assigned as SHV-135 in a duck origin E.coli.CMY-type AmpC β-lactamases weredetected in 5 E.coli,3 of which was CMY-2,and 2 of which were novel AmpC enzyme and had been assigned as CMY-64.The present study showed that the prevalence of ESBLs and AmpC complex and diversity among sick food-producing animals origin E.coli,the detection of ESBLs and AmpC was increasing,suggesting prude use of β-lactams in veterinary clinic.