ACTA VETERINARIA ET ZOOTECHNICA SINICA ›› 2016, Vol. 47 ›› Issue (4): 805-811.doi: 10.11843/j.issn.0366-6964.2016.04.021

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Investigation of Antimicrobial Agents Resistance Transferred Horizontally in Fluoroquinolone Resistant Escherichia coli from Swine

WANG Hong-dong,XU Guo-feng,JIAO Wei-wei,ZHANG Xiu-ying*   

  1. (College of Veterinary Medicine,Northeast Agricultural University,Harbin 150030,China)
  • Received:2015-07-15 Online:2016-04-23 Published:2016-04-23

Abstract:

In order to investigate the role of mobile plasmids in the horizontal transmission mechanism of drug resistance in Escherichia coli isolated from pigs,the conjugation experiments of fluoroquinolone resistance and PMQR genes positive Escherichia coli were carried out,the minimum inhibitory concentration(MIC) of 8 kinds of common drug in transconjugants were figured by using broth micro dilution method and the plasmid mediated quinolone resistance gene(PMQR) were detected by PCR methods with specific primers designed after the conjugation experiments.The results showed that 16 strains of bacteria were joined successfully within 41 strains of fluoroquinolone resistance and PMQR genes positive donors,successful rate of conjugation experiments was up to 39%,transconjugants showed kinds of resistant phenotypes compared with J53 strain through testing the figure of MIC values,and compared with donor strains,87.5% of the transconjugants reveals changes of drug resistance patterns and the phenomenon of missing a drug resistance with obtaining another drug resistance,the results of PCR showed the decline of gene phenotypes compared with donor strains,qnrS gene revealed the highest successful conjugation rate,the genes of oqxA and oqxB can transferred in the same mobile plasmid,12.5% of the transconjugants displayed that the genes of oqxAoqxB and qnrS can be transferred by the same mobile plasmid.The results above suggest that different PMQR genes show different success rates in the process of conjugation jointing with mobile plasmid which mediated resistance genes transferred horizontally in strains,which suggest the different PMQR genes may be located in the different mobile plasmid,by comparing the changes of drug resistance and gene phenotypes before and after conjugation experiments,especially the detection rate of PMQR gene,it can be preliminarily confirmed that the mobile plasmids play a very important role in the process that antimicrobial agents resistance genes are transferred horizontally in Escherichia coli strains.

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