河南省部分规模化奶牛场奶牛乳房炎源大肠杆菌耐药性分析与耐药基因检测

Drug resistance analysis and drug resistance gene detection of cow mastitis-derived Escherichia coli in some large-scale dairy farms in Henan Province

为了解规模化奶牛场乳房炎源大肠杆菌耐药现状和耐药基因分布情况,试验对采自河南省部分规模化奶牛场感染乳房炎奶牛的852份乳汁样本进行大肠杆菌的分离鉴定与16S rRNA基因PCR鉴定,对分离的大肠杆菌菌株进行药敏试验及耐药基因检测。结果表明:共分离鉴定224株大肠杆菌,分离率为26.29%。分离菌株对11种抗生素均有不同程度耐药性,其中对恩诺沙星、氟苯尼考、环丙沙星、四环素、阿莫西林、阿米卡星耐药比较严重,耐药率为63.39%~82.14%;对头孢他啶、头孢曲松耐药率相对较低,分别为22.32%、27.67%;对亚胺培南最敏感,耐药率为0。耐3种及以上抗生素菌株有193株,占86.16%。对不同奶牛场的85株大肠杆菌分离株进行耐药基因检测,共检测到11种耐药基因,未检出耐药基因tetM、blaVIM和blaNDM。酰胺醇类耐药基因floR携带率最高(为61.18%),喹诺酮类耐药基因oqxB(42.35%)、qnrS(44.71%)携带率和四环素类耐药基因tetA(30.59%)、tetB(38.82%)携带率相对较高,多重耐药基因检出率为51.76%。说明河南省部分地区规模化奶牛场乳房炎源大肠杆菌耐药性比较严重,携带多重耐药基因,建议临床上应根据药敏试验结果科学合理地选择抗生素,有效做好疫病防控。

In order to understand the current status of the drug resistance of cow mastitis-derived Escherichia coli and the distribution of drug resistance genes in large-scale dairy farms, the experiment was conducted to isolate and identify E. coli and 16S rRNA gene PCR identification from 852 milk samples collected from mastitis-infected cows in some large-scale dairy farms in Henan Province, and the isolated E. coli strains were detected for drug sensitivity test and drug resistance genes. The results showed that 224 E. coli isolates were isolated and identified, with an isolation rate of 26.29%, and the isolates were resistant to 11 antibiotics to different degrees, among which the resistance to enrofloxacin, fluphenazole, ciprofloxacin, tetracycline, amoxicillin and amikacin was relatively serious, with resistance rates ranging from 63.39% to 82.14%;the resistance rates to ceftazidime and ceftriaxone were relatively low, 22.32% and 27.67%, respectively;and they were most sensitive to imipenem, with a resistance rate of 0. There were 193 strains resistant to three and more antibiotics, accounting for 86.16%. The drug resistance genes were detected in 85 E. coli isolates from different dairy farms and 11 resistance genes were detected, and the resistance genes tetM, blaVIMand blaNDMwere not detected. The carriage rate of myclobutanol resistance gene floR was the highest, 61.18%;the carriage rates of quinolone resistance genes oqxB(42.35%) and qnrS(44.71%) and tetracycline resistance genes tetA(30.59%) and tetB(38.82%) were relatively high;the multi-drug resistance gene detection rate was 51.76%. The results suggested that the drug resistance of cow mastitis-derived Escherichia coli in some large-scale dairy farms in Henan Province was serious, and multiple drug resistance genes were carried. A recommendation was given that clinical antibacterial drugs should be selected scientifically and rationally according to the results of drug sensitivity test to effectively prevent and control the diseases.