Antibiotic resistance mechanism of Escherichia coli O157∶H7 against florfenicol
FENG Shi-wen1, 2, 3, LI Jun2, 3, ZENG Yun1, YANG Wei2, 3, CHEN Ze-xiang2, 3, PAN-yan2, 3, PENG Hao2, 3
1.College of Animal Science and Technology, Guangxi University, Nanning 530005, China; 2.Guangxi Veterinary Institute, Nanning 530001, China; 3.Guangxi Key Laboratory of Animal Vaccines and New Technology, Nanning 530001, China
Abstract：We investigated the antibiotic resistance mechanism of E. coli O157∶H7 against florfenicol. Two strains of E. coli O157∶H7 which 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∶H7 was detected by combination efflux pump inhibitors with florfenicol. Two strains of E. coli O157∶H7 were obtained antibiotic resistance after 36 times passage culture induced with florfenicol. Results of plasmids detection showed that 2 plasmids with 3 500 bp and 1 200 bp were emerging. The floR was located in the plasmid. The plasmid and the floR of 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∶H7 could efflux florfenicol. This study preliminarily confirmed that the floR and the function of the efflux pump of E. coli O157∶H7 contribute to the florfenicol resistance.
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2016, Vol. 32 
