合肥地区动物源致病性大肠杆菌ESBLs和PMQR基因流行分布

Prevalence of ESBLs and PMQR genes in pathogenic Escherichia coli isolated from animals in Hefei district

从安徽省合肥地区多个养殖厂分离鉴定了65株致病性大肠杆菌,用PCR方法检测ESBLs和PMQR基因的流行分布情况,用微量肉汤稀释法测定30株ESBLs和/或PMQR阳性菌对16种抗菌药物的最小抑菌浓度。PCR结果显示:ESBLs阳性率为24.6%(16/65),分别为blaOXA(16株)、blaTEM(15株)和blaCTX-M(14株),未检出blaSHV;PMQR的阳性率为46.2%(30/65),分别为qnrA(9株)、qnrS(18株)、aac(6′)-Ib-cr(28株),未检出qnrB、qnrC、qnrD和qepA;且携带ESBLs基因的阳性菌株均携带PMQR基因。首次检测出有7株大肠杆菌同时携带ES-BLs基因型(blaOXA、blaTEM、blaCTX-M)和PMQR基因型(qnrA、qnrS、aac(6′)-Ib-cr)。药物敏感性测定结果显示:30株携带ESBLs和/或PMQR基因的阳性大肠杆菌对16种抗菌药物的耐药率为16.7%～100%,耐药谱较广,耐药性较严重。16株同时携带ESBLs和PMQR基因的阳性菌株对11种及11种以上药物耐药的菌株占87.5%,14株仅携带PMQR基因的阳性菌株对11种及11种以上药物耐药的菌株占28.5%,表明携带PMQR基因的同时携带ESBLs基因大大增强了菌株的耐药性,携带耐药基因的数量和种类与菌株的多重耐药性相关。

Sixty five pathogenic Escherichia coli isolates were collected and identified from some breeding farms in Hefei district of Anhui province,prevalence of ESBLs and PMQR genes was detected by PCR, susceptibilities of 30 ESBLs-and/or PMQR-positive E. coli isolates to 16 antimicrobials were performed by broth micro-dilution method. The PCR results showed that ESBLs-positive rate was 24. 6%（16/65）,they were blaOXA（16）,blaTEM（15） and blaCTX-M（14）,no blaSHV was detected. PMQR-positive rate was 46.2 % （30/65）, they were qnrA（9）, qnrS（18）, aac （6＇） -Ib-cr（28）,no qnrB,qnrC,qnrD or qepA were detected,and positive strains that carried ES- BLs genes also carried PMQR genes. We firstly detected that there were 7 E. coli isolates carried both ESBLs genes （blaOXA, blaTEM, blaCTX-M） and PMQR genes （ qnrA, qnrS, aac （ 6＇） -Ib-cr）. Susceptibility test results showed that drug-resistance rate of 30 E. coli isolates carried ESBLs genes and （or） PMQR genes to 16 antimicrobials ranged from 16.7% to 100% ,which meant a serious resistance and wide resistance spectrum. Drug-resistance rate of the 16 E. coliisolates carried both ESBLs and PMQR genes to more than 11 antimicrobials is 87.5 %, however, drug-resistance rate of 14 E. coli isolates carried only PMQR genes is only 28.5% under the same circumstance,it suggested that the existence of PMQR genes plus ESBLs genes enhance the isolates＇ resistance,amounts and species of resistance genes are related with these isolates＇ multi-drug resistance.