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

<sec>
<h3>Introduction</h3>
<p>To understand the prevalence of avian methicillin-resistant <italic>Staphylococcus aureus</italic> (MRSA) and the current status of drug resistance in Qingdao, a comprehensive molecular epidemiological investigation and analysis of evolutionary relationships of MRSA isolates from broiler and layer chickens and waterfowl was conducted.</p>
</sec>
<sec>
<h3>Material and Methods</h3>
<p>One hundred and two avian MRSA strains were identified by multi-locus sequence typing, staphylococcal protein A (<italic>spa</italic>) and staphylococcal cassette chromosome <italic>mec</italic> (SCCmec) typing, and whole-genome sequencing.</p>
</sec>
<sec>
<h3>Results</h3>
<p>The sequence type (ST) 9-t899-SCC<italic>mec</italic> IVb type represented the highest proportion of avian-derived MRSA strains (71.57%), with ST398 type strains occasionally observed in broilers and waterfowl. The poultry-derived MRSA strains were all resistant to eight or more antimicrobials. Avian-derived MRSA strains carried 20 resistance genes, 109 virulence genes and 10 plasmids. Strains carrying the <italic>cfr</italic> oxazolidinone resistance gene were occasionally seen in broiler- and layer-derived MRSA. Single nucleotide polymorphism (SNP) core genome evolution and locus difference analysis showed that the closest strains were all of ST9-t899 type (to which also affiliated the highest number of strains) and this type occurred on all three kinds of poultry farm, but the SNP difference loci between strains of the same type ranged from 0 to 1472.</p>
</sec>
<sec>
<h3>Conclusion</h3>
<p>The dominant type of MRSA from different poultry sources in Qingdao is ST9-t899-SCC<italic>mec</italic> IVb, which is commonly resistant to a variety of antimicrobial drugs and carries a variety of resistance genes and a large number of virulence genes. Sequence type 9-t899 type is widely spread among the three kinds of poultry investigated, but there are differences in affiliations.</p>
</sec>
</abstract>

Introduction
To understand the prevalence of avian methicillin-resistant Staphylococcus aureus (MRSA) and the current status of drug resistance in Qingdao, a comprehensive molecular epidemiological investigation and analysis of evolutionary relationships of MRSA isolates from broiler and layer chickens and waterfowl was conducted.


Material and Methods
One hundred and two avian MRSA strains were identified by multi-locus sequence typing, staphylococcal protein A (spa) and staphylococcal cassette chromosome mec (SCCmec) typing, and whole-genome sequencing.


Results
The sequence type (ST) 9-t899-SCCmec IVb type represented the highest proportion of avian-derived MRSA strains (71.57%), with ST398 type strains occasionally observed in broilers and waterfowl. The poultry-derived MRSA strains were all resistant to eight or more antimicrobials. Avian-derived MRSA strains carried 20 resistance genes, 109 virulence genes and 10 plasmids. Strains carrying the cfr oxazolidinone resistance gene were occasionally seen in broiler- and layer-derived MRSA. Single nucleotide polymorphism (SNP) core genome evolution and locus difference analysis showed that the closest strains were all of ST9-t899 type (to which also affiliated the highest number of strains) and this type occurred on all three kinds of poultry farm, but the SNP difference loci between strains of the same type ranged from 0 to 1472.


Conclusion
The dominant type of MRSA from different poultry sources in Qingdao is ST9-t899-SCCmec IVb, which is commonly resistant to a variety of antimicrobial drugs and carries a variety of resistance genes and a large number of virulence genes. Sequence type 9-t899 type is widely spread among the three kinds of poultry investigated, but there are differences in affiliations.

Molecular epidemiological characteristics and genetic evolutionary relationships of methicillin-resistant <italic>Staphylococcus aureus</italic> of different avian origins in Qingdao, China, using whole-genome sequencing

Journal of Veterinary Research

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

Molecular epidemiological characteristics and genetic evolutionary relationships of methicillin-resistant  of different avian origins in Qingdao, China, using whole-genome sequencing

Introduction
To understand the prevalence of avian methicillin-resistant Staphylococcus aureus (MRSA) and the current status of drug resistance in Qingdao, a...

Molecular epidemiological characteristics and genetic evolutionary relationships of methicillin-resistant Staphylococcus aureus of different avian origins in Qingdao, China, using whole-genome sequencing

Published Online: Jun 16, 2023

Page range: 169 - 177

Received: Nov 02, 2022

Accepted: Jun 12, 2023

DOI: https://doi.org/10.2478/jvetres-2023-0035

Keywords
MRSA, poultry, whole genome sequencing, SNP

© 2023 Zhen Xiao et al., published by Sciendo

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

Molecular epidemiological characteristics and genetic evolutionary relationships of methicillin-resistant Staphylococcus aureus of different avian origins in Qingdao, China, using whole-genome sequencing

Published Online: Jun 16, 2023

Page range: 169 - 177

Received: Nov 02, 2022

Accepted: Jun 12, 2023

DOI: https://doi.org/10.2478/jvetres-2023-0035

KeywordsMRSA, poultry, whole genome sequencing, SNP

© 2023 Zhen Xiao et al., published by Sciendo

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

Keywords
MRSA, poultry, whole genome sequencing, SNP