<abstract xmlns="http://www.w3.org/1999/xhtml">

<sec id="j_jvetres-2022-0055_s_005"><h3>Introduction</h3>
<p><italic>Escherichia coli</italic> is a widespread environmental pathogen frequently causing dairy cow mastitis. This bacterium is particularly capable of acquiring antimicrobial resistance, which can have severe impacts on animal food safety and human health. The objective of the study was to investigate antimicrobial resistance and genetic correlations of <italic>E. coli</italic> from dairy cow mastitis cases in northern China.</p></sec>
<sec id="j_jvetres-2022-0055_s_006"><h3>Material and Methods</h3>
<p>Forty strains of <italic>E. coli</italic> from 196 mastitis milk samples were collected, susceptibility to 13 common antibiotics and the prevalence of resistance genes were tested in these strains, and the genetic characteristics were identified by multilocus sequence typing.</p></sec>
<sec id="j_jvetres-2022-0055_s_007"><h3>Results</h3>
<p>The results showed that most isolates were multidrug resistant (MDR) (75%), and the resistance rates to cefazolin, trimethoprim-sulfamethoxazole and ampicillin were 77.5%, 55.0%, and 52.5%, respectively. The representative genes of the isolates were <italic>aadA</italic> (62.5%) and <italic>tet</italic>(B) (60.0%). Multilocus sequence typing showed 19 different sequence types (STs) and 5 clonal complexes (CCs) in the 40 isolates, mainly represented by ST10 and CC10. The strains of the same ST or CC showed a high level of genetic relatedness, but the characteristics of their antimicrobial resistance were markedly different.</p></sec>
<sec id="j_jvetres-2022-0055_s_008"><h3>Conclusion</h3>
<p>Most <italic>E. coli</italic> isolates in the study were MDR strains. Some strains of the same ST or CC showed diverse resistance characteristics to common antimicrobials. Therefore, <italic>E. coli</italic> from dairy cow mastitis in northern China should be investigated to elucidate its antimicrobial resistance and genotypes.</p>
</sec></abstract>

Introduction
Escherichia coli is a widespread environmental pathogen frequently causing dairy cow mastitis. This bacterium is particularly capable of acquiring antimicrobial resistance, which can have severe impacts on animal food safety and human health. The objective of the study was to investigate antimicrobial resistance and genetic correlations of E. coli from dairy cow mastitis cases in northern China.
Material and Methods
Forty strains of E. coli from 196 mastitis milk samples were collected, susceptibility to 13 common antibiotics and the prevalence of resistance genes were tested in these strains, and the genetic characteristics were identified by multilocus sequence typing.
Results
The results showed that most isolates were multidrug resistant (MDR) (75%), and the resistance rates to cefazolin, trimethoprim-sulfamethoxazole and ampicillin were 77.5%, 55.0%, and 52.5%, respectively. The representative genes of the isolates were aadA (62.5%) and tet(B) (60.0%). Multilocus sequence typing showed 19 different sequence types (STs) and 5 clonal complexes (CCs) in the 40 isolates, mainly represented by ST10 and CC10. The strains of the same ST or CC showed a high level of genetic relatedness, but the characteristics of their antimicrobial resistance were markedly different.
Conclusion
Most E. coli isolates in the study were MDR strains. Some strains of the same ST or CC showed diverse resistance characteristics to common antimicrobials. Therefore, E. coli from dairy cow mastitis in northern China should be investigated to elucidate its antimicrobial resistance and genotypes.

Analysis of antimicrobial resistance and genetic correlations of <italic>Escherichia coli</italic> in dairy cow mastitis

Journal of Veterinary Research

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Analysis of antimicrobial resistance and genetic correlations of  in dairy cow mastitis

Introduction
Escherichia coli is a widespread environmental pathogen frequently causing dairy cow mastitis. This bacterium is particularly capable of acquiring...

Analysis of antimicrobial resistance and genetic correlations of Escherichia coli in dairy cow mastitis

Published Online: Nov 04, 2022

Page range: 571 - 579

Received: Mar 23, 2022

Accepted: Sep 28, 2022

DOI: https://doi.org/10.2478/jvetres-2022-0055

Keywords
molecular characteristics, antimicrobial resistance, genetic correlation, dairy cow mastitis

© 2022 K. Li et al. published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Analysis of antimicrobial resistance and genetic correlations of Escherichia coli in dairy cow mastitis

Published Online: Nov 04, 2022

Page range: 571 - 579

Received: Mar 23, 2022

Accepted: Sep 28, 2022

DOI: https://doi.org/10.2478/jvetres-2022-0055

Keywordsmolecular characteristics, antimicrobial resistance, genetic correlation, dairy cow mastitis

© 2022 K. Li et al. published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Keywords
molecular characteristics, antimicrobial resistance, genetic correlation, dairy cow mastitis