摘要
目的研究大肠杆菌O157∶H7(E.coli O157∶H7)对氟苯尼考耐药性产生的机制。方法本研究采用亚抑菌浓度体外耐药诱导的方法将E.coli O157∶H7诱导成为氟苯尼考高度耐药菌株,采用无抗生素压力下连续传代培养或SDS方法将耐药菌株的氟苯尼考耐药性消除,使用PCR方法检测氟苯尼考耐药基因floR,通过外排泵抑制剂与氟苯尼考联合使用,检测E.coli O157∶H7是否存在对氟苯尼考的主动外排作用。结果经过36代的耐药诱导,敏感菌株对氟苯尼考产生了高度耐药(MIC为256μg/mL)。质粒检测结果显示,耐药诱导菌株出现2个质粒,大小分别约为3 500bp和1 200bp,floR基因位于质粒DNA中。经连续传代培养或SDS法进行耐药消除,耐药诱导菌株对氟苯尼考的敏感性提高,但其质粒和floR基因均未丢失。结论 E.coli O157∶H7氟苯尼考敏感菌和耐药菌均存在对氟苯尼考的质子驱动型外排泵和ATP水解依赖型外排泵主动外排作用。
We investigated the antibiotic resistance mechanism of E.coli O157∶ H7 against florfenicol.Two strains of E.coli O157∶H7which were sensitive to florfenicol were induced to be drug resistant strains by subinhibitory concentration,and the florfenicol resistance was eliminated by continuous subcultured without antibiotic pressure or with SDS.The florfenicol resistance gene floR was detected by PCR,and the efflux pump which efflux florfenicol of E.coli O157∶H7was detected by combination efflux pump inhibitors with florfenicol.Two strains of E.coli O157∶H7were obtained antibiotic resistance after36 times passage culture induced with florfenicol.Results of plasmids detection showed that 2plasmids with 3 500 bp and1 200 bp were emerging.The floR was located in the plasmid.The plasmid and the floRof the resistant strains had not been lost after continuous subculture without antibiotic pressure or with SDS,and both florfenicol sensitive strain and resistant strain of E.coli O157∶H7could efflux florfenicol.This study preliminarily confirmed that the floRand the function of the efflux pump of E.coli O157∶H7contribute to the florfenicol resistance.
出处
《中国人兽共患病学报》
CAS
CSCD
北大核心
2016年第3期271-275,共5页
Chinese Journal of Zoonoses
基金
广西科技重大专项(桂科重14121003-4-1)
广西自然科学基金(桂科自2013GXNSFAA019093)
广西水产畜牧兽医局科研专项(桂渔牧科201528005)~~
作者简介
通讯作者：曾芸，Email：yzeng323@163．com
