规模化牧场154株奶牛乳腺炎源大肠杆菌的耐药性分析

Drug resistance analysis of 154 strains of cow mastitis-derived Escherichia coli in large-scale farms

为了解规模化牧场中奶牛乳腺炎源大肠杆菌的耐药性,试验采集安徽、福建、广东、江苏及内蒙古等省(自治区)的11个规模化牧场的临床型乳腺炎奶牛的乳样进行细菌分离纯化,采用基质辅助激光解吸电离飞行时间质谱(MALDI-TOF-MS)方法对分离株进行鉴定,采用K-B纸片扩散法检测大肠杆菌对11种常用抗生素的耐药性。对乳腺炎源大肠杆菌多重耐药性及不同地区大肠杆菌的耐药性进行分析。结果表明:共分离到154株大肠杆菌,分离率为22.95%,其中安徽60株,广东42株,福建22株,江苏16株,内蒙古10株,其他地区4株。154株大肠杆菌对青霉素、阿莫西林、链霉素、氨苄西林耐药性较强,耐药率分别为98.05%、61.69%、42.21%、40.91%;对庆大霉素、环丙沙星、氟苯尼考和阿米卡星相对敏感,敏感率分别为90.26%、73.38%、68.83%和61.04%;经多重耐药性分析,90株(占58.44%)大肠杆菌对3种及以上抗生素耐药,其中30株大肠杆菌对6种抗生素耐药;多重耐药菌株中,耐药谱为氨苄西林(AMP)-青霉素(PEN)-阿莫西林(AMX)-头孢氨苄(LEX)-四环素(STR)-链霉素(TCY)的大肠杆菌菌株最多,占18.83%;大肠杆菌耐药性在不同地区间存在差异,其中安徽、福建和内蒙古地区奶牛乳腺炎源大肠杆菌耐药性比较严重。说明奶牛乳腺炎源大肠杆菌在我国规模化牧场中具有明显的多重耐药性,提示牧场在生产中应加强饲养管理,合理使用药物。

In order to understand the drug resistance of cow mastitis-derived Escherichia coli(E.coli)in large-scale farms,milk samples from 11 large-scale farms in Anhui,Fujian,Guangdong,Jiangsu,Inner Mongolia and other Provinces(Autonomous Regions)were collected for bacterial isolation and purification.The isolates were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry(MALDI-TOF-MS),and the resistance of E.coli to 11 commonly used antibiotics was detected by K-B paper diffusion method.Multi-drug resistance of E.coli of mastitis origin and resistance of E.coli in different regions were analysed.The results showed that 154 E.coli strains were isolated,including 60 strains from Anhui Province,42 strains from Guangdong Province,22 strains from Fujian Province,16 strains from Jiangsu Province,10 strains from Inner Mongolia Autonomous Region and 4 strains from other regions.154 strains of E.coli were highly resistant to penicillin,amoxicillin,streptomytin and ampicillin,with resistance rates of 98.05%,61.69%,42.21%and 40.91%,respectively,and were relatively sensitive to gentamicin,ciprofloxacin,florfenicol and amikacin,with sensitivity rates of 90.26%,73.38%,68.83%and 61.04%,respectively.As determined by multi-drug resistance analysis,90 strains(58.44%)of E.coli were resistant to three or more antibiotics,including 30 strains of E.coli resistant to 6 antibiotics.Among multidrug-resistant bacteria,E.coli with ampicillin(AMP)-penicillin(PEN)-amoxicillin(AMX)-cephalexin(LEX)-tetracycline(STR)-streptomycin(TCY)resistance spectrum was the most numerous,accounting for 18.83%.The drug resistance of E.coli varied among different regions,among which E.coli resistance in dairy cows with mastitis was more serious in Anhui Province,Fujian Province and Inner Mongolia Autonomous Region.The results suggested that cow mastitis-derived E.coli had obvious multi-drug resistance in large-scale farms in China,which inferred that farms should strengthen feeding management and use drugs rationally in production.