鸡源大肠杆菌对β-内酰胺类药物的耐药性分析和耐药基因检测

Detection of drug resistance and resistance genes of Escherichia coli isolated from chickens toβ-lactam antibiotics

为研究江苏部分地区鸡源大肠杆菌对β-内酰胺类抗菌药物的耐药情况和耐药基因,分析其耐药表型与耐药基因的相关性,以K-B纸片扩散法对分离的20株鸡源大肠杆菌进行11种β-内酰胺类药物的敏感性分析,PCR法检测bla_(CTX-M-1)、bla_(CTX-M-2)、bla_(CTX-M-8)、bla_(CTX-M-9)、bla_(TEM)与bla_(SHV)等6种耐药基因携带情况。结果显示:20株鸡源大肠杆菌对β-内酰胺类药物的耐药率较高,其中苯唑西林为100%,氨苄西林为75%,头孢呋辛为70%,对头孢哌酮、头孢曲松的耐药率最低,均为30%,且分离菌株表现为多重耐药;共检出3种耐药基因,bla_(CTX-M-1)、bla_(TEM)、bla_(SHV),检出率分别为85%、30%、30%,7株分离菌同时携带2种及以上耐药基因,占比35%(7/20);11种β-内酰胺类药物与blaCTX-M-1基因的符合率较高,均达85%以上,与bla_(SHV)基因的符合率相对低些,均在40%以下,且耐药表型与耐药基因型并不完全吻合。提示:江苏部分地区鸡源大肠杆菌对β-内酰胺类药物的耐药问题比较严重,应加强当地鸡源大肠杆菌的耐药性监测,从而选择合适的药物防治鸡大肠杆菌病。

To detect the drug resistance of Escherichia coli isolated from chickens in some areas of Jiangsu Province,K-B disk diffusion method was used to test the drug sensitivity of 20 E.coli strains isolated from chickens to 11β-lactam antibiotics.Furthermore,six resistance genes toβ-lactam antibiotics,including bla_(CTX-M-1)、bla_(CTX-M-2)、bla_(CTX-M-8)、bla_(CTX-M-9)、bla_(TEM)and bla_(SHV),were detected by PCR to analyze the correlation between the resistance phenotypes and resistance genes.The results showed that 20 strains of E.coli exhibited a high resist-ance rate toβ-lactams,of which benzoxacillin was 100%,ampicillin was 75%,cefuroxime was 70%;and the resistance rate to cefopera-zone and ceftriaxone was the lowest,which was 30%.These isolates showed multi-drug resistance.Three resistance genes were detected,bla_(CTX-M-1),bla_(TEM),and bla_(SHV),with the detection rates of 85%,30%,and 30%,respectively.Seven isolated strains carried 2 or more resist-ance genes,accounting for 35%of the whole(7/20).The 11β-lactam antibiotics showed a high rate of concordance with bla_(CTX-M-1)at 85%and above,and a relatively low rate of concordance with the blaSHV,below 40%;but the resistance phenotype and resistance genes did not match exactly.The present study suggested that the drug resistance of E.coli toβ-lactams was a serious problem in some areas of Jiangsu Province,and surveillance of local drug-resistant bacteria should be strengthened so that appropriate drugs could be selected for the control of E.coli diseases in chickens there.