广东地区鱼源大肠埃希菌ESBLs和PMQR流行分布调查

从广东地区食用鱼肠道分离鉴定了218株大肠埃希菌,用琼脂稀释法测定218株大肠埃希菌对17种抗菌药物的敏感性,并用PCR方法调查ESBLs和PMQR基因的流行分布情况.对10株β-内酰胺酶(包括ESBLs)和/或PMQR阳性菌株进行了接合转移试验,探讨ESBLs和PMQR基因的传播机制.敏感性测定结果显示:218株大肠埃希菌对17种抗菌药物的耐药率为0.5%～72.5%.在112株氨苄西林耐药菌株中,检测出2种ESBLs基因,分别为blaCTX-M-79和blaCTX-M-14,2株菌中还检测到β-内酰胺酶基因blaLEN-4和blaLEN-17.在80株环丙沙星耐药菌株中,检测到59株为PMQR阳性,分别为qnrB(33株),qnrD(5株),qnrS(21株),aac(6’)-Ib-cr(6株).接合转移试验结果表明,ESBLs和/或PMQR基因可同时存在于一个质粒上进行转移.

Prevalence of ESBLs and PMQR Encoding Genes in Escherichia coli Isolated from Edible Fish in Guangdong

Two hundred and eighteen Escherichia coli isolates were collected and identified from edible fish in this study.Susceptibilities of 218 isolates to 17 antimicrobials were performed by agar dilution method.Prevalence of ESBLs and PMQR encoding genes was detected by PCR.Broth mating was applied to explore the transfer of ESBLs and/or PMQR determinants from 10 ESBLs and/or PMQR positive isolates to E.coli C600.Susceptibility results showed that resistance occurance of 218 E.coli to 17 antimicrobials ranged from 0.5% to 72.5%.Two ESBLs encoding genes were detected in 112 ampicillin-resistant isolates,including blaCTX-M-79 and blaCTX-M-14.Beta-lactamase genes,blaLEN-4 and blaLEN-17 were also detected in 2 isolates.Fifty-nine of 80 ciprofloxacin-resistant isolates harboured PMQR determinants,of which 33 were qnrB,5 qnrD,21 qnrS,and 6 aac(6′)-Ib-cr.No isolates were detected to carry qnrA,qnrC and qepA.The results of conjugation experiments showed that ESBLs and/or PMQR determinants may be transferred on a same plasmid to E.coli C600.