目的 了解广州市宠物源大肠埃希菌Escherichia coli耐药性和耐药基因携带情况。方法 2016年7月至2017年7月从广州市4家宠物医院采集健康或患病犬猫样品共319份，其中，健康动物127份，患病动物192份。采用选择性培养基分离大肠埃希菌，利用基质辅助激光解析串联飞行时间质谱仪（MALDI-TOF MS）鉴定菌种；采用琼脂稀释法测定大肠埃希菌对11种抗菌药物的敏感性，利用PCR和测序检测耐药基因的携带情况。结果 319份样品共分离得到大肠埃希菌203株，其中，患病动物源109株，健康动物源94株。203株大肠埃希菌中有179株至少对1种抗生素耐药；对氨苄西林耐药率最高（76.85%），对头孢噻肟、四环素、多西环素和磺胺甲噁唑-甲氧苄啶耐药率均高于50%；对阿米卡星最为敏感，耐药率仅为10.84%。患病动物源大肠埃希菌对11种抗菌药物的耐药率均高于健康动物源，除阿米卡星、氟苯尼考和磷霉素外，对其他药物的耐药性均差异极显著（P < 0. 01）。耐药基因检测结果显示，floR 检出率最高（检出率为34.97%），blaCTX-M-9G、blaCTX-M-1G、fosA3、rmtB和blaCMY-2检出率分别为22.66%、20.19%、17.73%、10.34%和1.48%，未检测到blaCTX-M-2G和blaCTX-M-25G。结论 广州地区宠物源大肠埃希菌耐药状况严峻，且常携带多种重要耐药基因。应当加强对宠物源细菌耐药性的监测。
Objective To investigate antimicrobial resistance and resistance genes of Escherichia coli from pet animals in Guangzhou.Method From July 2016 to July 2017, 319 samples were collected from cats and dogs at four animal hospitals in Guangzhou, including 127 samples from healthy animals and 192 samples from diseased animals. E. coli strains were isolated using the selective media, and were identified by MALDI-TOF mass spectrometry. The susceptibilities of E. coli isolates to 11 antimicrobial agents were determined by the agar dilution method. The presence of resistance genes was determined by PCR and sequencing.Result A total of 203 E. coli strains were isolated from 319 samples, including 109 E. coli isolates from diseased animals and 94 E. coli isolates from healthy animals. Among the 203 strains, 179 strains were resistant to at least one antimicrobial agent. The isolates showed the highest resistance rate against ampicillin (76.85%). The resistance rates against cefotaxime, tetracycline, doxycycline and sulfamethoxazole-trimethoprim were above 50%. The isolates were the most susceptible to amikacin with the resistance rate of only 10.84%. The isolates from diseased animals showed higher resistance rates against all antimicrobial agents compared with those from healthy animals. The resistance rates against all antimicrobial agents except amikacin, florfenicol and fosfomycin were significantly higher in the isolates from diseased animals compared with healthy animals (P < 0.01). The detection results of resistance genes showed that floR had the highest detection rate (34.97%), the detection rates of blaCTX-M-9G, blaCTX-M-1G, fosA3, rmtB and blaCMY-2 genes were 22.66%, 20.19%, 17.73%,10.34% and 1.48% respectively. The genes blaCTX-M-2G and blaCTX-M-25G were not detected.Conclusion The antimicrobial resistance of E. coli isolates from pet animals in Guangzhou has become a serious problem, and some isolates carry several important resistance genes. Antimicrobial resistance in pet animals requires strict monitoring.