›› 2019, Vol. 46 ›› Issue (5): 1499-1507.doi: 10.16431/j.cnki.1671-7236.2019.05.029

• Basic Veterinary Medicine • Previous Articles     Next Articles

Cross-resistance of Antimicrobials and Disinfectants of Escherichia coli from Neijiang City

YANG Wen1, CHEN Hongwei2, ZENG Yangmei3, WU Junwei2   

  1. 1. Neijiang Vocational & Technical College, Neijiang 641100, China;
    2. College of Animal Science, Southwest University, Rongchang 402460, China;
    3. Chongqing Bull Animal Pharmaceutical Company, Ltd., Rongchang 402460, China
  • Received:2018-11-16 Online:2019-05-20 Published:2019-05-20

Abstract:

This study was aimed to understand the degree and mechanism of cross resistance of Escherichia coli isolated from some pig farms in Neijiang city to antimicrobials and disinfectants.The minimal inhibitory concentration (MIC) values for enrofloxacin,oxytetracycline,benzalkonium bromide and glutaraldehyde of 66 strains of Escherichia coli isolated from some pig farms in Neijiang city were determined using broth microdilution method and selected cross resistance strains that were resistant to antimicrobials and disinfectants.Whether the cross resistance strains had qacE△1,acrA,acrB and tolC genes was detected by PCR technology and agarose gel electrophoresis.And the mutation of acrA,acrB and tolC genes of these strains were determined.All the 66 strains were resistant to enrofloxacin and oxytetracycline,and three strains (named as No.5,No.6 and No.7) were resistant to benzalkonium bromide,but no strains were resistant to glutaraldehyde.It showed that there were three strains were cross resistance strains.All the three cross resistance strains had acrA,acrB and tolC genes,but only No.6 had qacE△1 gene.All the genes acrA,acrB and tolC of the three strains occurred mutation,and the amino acid that transcribed by these genes also occurred mutation.The highest and lowest base mutation rate were 2.10% (No.7's tolC gene) and 0.97% (No.7's acrA gene).The highest and lowest amino acid mutation rate were 2.39% (No.7's acrB gene) and 0.22% (tolC gene of No.5,No.6 and No.7).And some mutation occurred at the same base site or the same amino acid site.All the 66 strains isolated from some pig farms in Neijiang city were resistant to enrofloxacin and oxytetracycline,and there were cross resistance strains that were resistant to antimicrobials and disinfectants,and the cross resistance mechanism of these strains might related to the efflux pumb AcrAB-TolC.

Key words: Escherichia coli; disinfectant; antimicrobials; cross resistance

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