中文摘要：

本试验旨在了解屠宰前鸡、猪源食品动物体内大肠杆菌耐药情况，分析潜在的食品安全问题。从广州市畜禽交易市场随机采集待屠宰鸡和猪的粪便样品，分离鉴定大肠杆菌，并采用琼脂稀释法检测大肠杆菌对15种抗菌药物的敏感性。结果显示，从658份猪源样品和133份鸡源样品中共分离鉴定出731株大肠杆菌，其中猪源606株，鸡源125株。药敏试验结果显示，731株大肠杆菌均表现出不同程度的耐药，耐药谱广且多重耐药现象严重。对复方新诺明和四环素的耐药率为90．0%以上，仅对头孢西丁、黏菌素和阿米卡星较敏感（耐药率均低于3％）。鸡源大肠杆菌对头孢噻肟、头孢曲松、新霉素、阿米卡星、萘啶酸和环丙沙星的耐药率显著高于猪源大肠杆菌（P〈0．05）。鸡源大肠杆菌中3耐及3耐以上的菌株占97．60％，猪源大肠杆菌占94．72％。结果表明，屠宰前畜禽体内大肠杆菌对临床常用抗菌药物的耐药性非常严重，以多重耐药为主，且耐药谱丰富多样。提示屠宰前畜禽携带的耐药菌对食品安全和人类健康存在较大的安全隐患。

英文摘要：

The study was aimed to determine the antimicrobial susceptibility of E. coli strains to common antimicrobials, soas to evaluate the potential food safety. E. coli strains were isolated from chicken and swine fecal samples which were randomlycollected from pig and poultry markets in Guangzhou. Antimicrobial susceptibility of 15 antimicrobial agents was determined byagar dilution method. A total of 606 and 125 E. coli strains were isolated from 658 swine samples and 133 chicken samples, re-spectively. 731 E. coli stains all displayed a different degree of resistance to 15 antimicrobials and showed multiple-antibiotic re-sistant phenotype. The resistance rates of sulfamethoxazole and tetracycline were over 90.0 %. There was a relative low fre-quency of resistance to cefoxitin, colistin and amikacin among these isolates, and resistance rates were less than 3 %. Chicken i-solates showed significantly higher frequency of resistance to cefotaxime, ceftriaxone, neomycin, amikacin, nalidixic acid andeiprofloxacin than pig isolates （P〈0. 05）. About 97. 6%chicken isolates and 94.72% pig isolates showed resistant to morethan 3 kinds of antimierobials. Antibiotic resistance of E. coil recovered from pigs and chickens at slaughter was serious, mostof them showed multiple resistance phenotypes. It indicated that these resistant bacteria carried by food animals at slaughtermight pose great threat to food safety and human healthy.