牛肉源大肠杆菌的耐药性检测及相关耐药基因分布

为了解牛肉源大肠杆菌的耐药性并检测其相关耐药基因分布,本研究选取了117株牛肉源大肠杆菌,经药敏纸片法对11种抗菌药物进行了药敏检测,并根据耐药表型利用普通和(或)多重PCR技术对耐四环素菌中tet(A)、tet(B)和tet(C)基因,耐氨苄西林菌中blaTEM1、blaPSE1和blaOXA1基因,耐链霉素菌中strA-strB、aadA1基因,耐磺胺类药菌中sul1、sul2和sul3基因进行了调查分析。结果显示,117株大肠杆菌对四环素、氨苄西林、链霉素和磺胺异恶唑的耐药率较高,分别为89%、42%、38%和22%。tet(A)基因是所有四环素耐药基因中最为流行的一种基因(55%);在检测的3个β-内酰胺类药物耐药基因中,最流行的为blaTEM1基因(73%);链霉素的耐药性主要由strA-strB基因(38%)编码;sul2基因在耐磺胺异恶唑菌中的检出率最高(77%)。结果表明本次分离的牛肉源大肠杆菌耐药非常严重,进一步肯定了肉牛业生产中抗菌药的使用对大肠杆菌耐药性的产生和发展所发挥的重要作用,提示食品动物养殖应严格控制饲料中抗菌药的滥用。

Detection of Antibiotic Resistance and Distribution of Resistance Determinants in Escherichia coli Isolated from Beef

To investigate the antibiotic resistance and resistance genes in Escherichia coli (E.coli) isolated from beef,susceptibilities to 11 antibiotics were conducted on 117 isolates,antibiotic resistance determinants were detected by using conventional and/or multiple PCR.The results showed that resistance rates of 117 isolates to tetracycline,ampicillin,streptomycin,sulfisoxazole were 89%,42%,38%,22%,respectively.As revealed by detecting resistance determinants,tet(A),bla_TEM1,strA-strB,sul2 were the most prevalent genes among tetracycline-resistant isolates,ampicillin-resistant isolates,streptomycin-resistant isolates and sulfisoxazole-resistant isolates,respectively.The detection rates of tet(A),bla_TEM1,strA-strB and sul2 were 55%,73%,38% and 77%,respectively.The conclusion was that E.coli isolated from beef was seriously resistant to antibiotics,and antibiotics administration in beef cattle industry promoted the emergence and the propagation of antibiotic resistance in E.coli.Data reported here clearly emphasized the need for a stricter application of antibiotics restriction policies in feedlot setting.