This study was conducted to determine the phenotypic and genotypic characteristics of multidrug-resistant (MDR) avian pathogenic Escherichia coli (APEC). A total of 54 MDR APEC were divided into 23 serotypes, and O78 (16.6%) was the most frequently observed. The MDR APEC carried β-lactamase–encoding genes (38.9%), integrons (61.6%), plasmid-mediated quinolone–resistant genes (20.4%), tetracycline-resistant genes (79.6%), sulfonamide-resistant genes (40.7%), and chloramphenicol-resistant genes (18.5%). Phylogenetic group D (44.4%), which is associated with extraintestinal strains, was the most frequently observed, but all MDR APEC, including groups A, B1, and B2, carried one or more virulence genes. This study analyzed the phenotypic and genotypic characterization in MDR APEC isolated from broilers with colibacillosis in Korea. It is important to monitor the occurrence of resistance genes in APEC. These bacteria may pose serious therapeutic problems when treating sick broilers. The MDR strains carried by animals and birds can enter the human food chain through the consumption of meat or other animal or poultry products.

进行这项研究是为了确定多重耐药（MDR）禽致病性大肠杆菌（APEC）的表型和基因型特征。）。共有54种MDR APEC分为23种血清型，其中最常见的是O78（16.6％）。MDR APEC携带β-内酰胺酶编码基因（38.9％），整合素（61.6％），质粒介导的喹诺酮耐药基因（20.4％），四环素耐药基因（79.6％），磺酰胺耐药基因（40.7％）和氯霉素抗性基因（18.5％）。与肠外毒株相关的系统发育D组（44.4％）是最常观察到的，但是所有MDR APEC，包括A，B1和B2组，都携带一个或多个毒力基因。这项研究分析了从韩国患有大肠杆菌病的肉鸡中分离出的MDR APEC的表型和基因型特征。监测APEC中抗性基因的发生很重要。这些细菌在治疗生病的肉鸡时可能会带来严重的治疗问题。