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

<sec>
<h3>Introduction</h3>
<p><italic>Streptococcus agalactiae (S. agalactiae)</italic> is a pathogen causing bovine mastitis that results in considerable economic losses in the livestock sector. To understand the distribution and drug resistance characteristics of <italic>S. agalactiae</italic> from dairy cow mastitis cases in China, multilocus sequence typing (MLST) was carried out and the serotypes and drug resistance characteristics of the bacteria in the region were analysed.</p>
</sec>
<sec>
<h3>Material and Methods</h3>
<p>A total of 21 strains of bovine <italic>S. agalactiae</italic> were characterised based on MLST, molecular serotyping, antimicrobial susceptibility testing, and the presence of drug resistance genes.</p>
</sec>
<sec>
<h3>Results</h3>
<p>The serotypes were mainly Ia and II, accounting for 47.6% and 42.9% of all serotypes, respectively. Five sequence types (STs) were identified through MLST. The ST103 and ST1878 strains were predominant, with rates of 52.4% and 28.6%, respectively. The latter is a novel, previously uncharacterised sequence type. More than 90% of <italic>S. agalactiae</italic> strains were susceptible to penicillin, oxacillin, cephalothin, ceftiofur, gentamicin, florfenicol and sulfamethoxazole. The bacteria showed high resistance to tetracycline (85.7%), clindamycin (52.1%) and erythromycin (47.6%). Resistant genes were detected by PCR, the result of which showed that 47.6%, 33.3% and 38.1% of isolates carried the <italic>tet(M)</italic>, <italic>tet(O)</italic> and <italic>erm(B)</italic> genes, respectively.</p>
</sec>
<sec>
<h3>Conclusion</h3>
<p>The results of this study indicate that <italic>S. agalactiae</italic> show a high level of antimicrobial resistance. It is necessary to monitor the pathogens of mastitis to prevent the transmission of these bacteria.</p>
</sec>
</abstract>

Introduction
Streptococcus agalactiae (S. agalactiae) is a pathogen causing bovine mastitis that results in considerable economic losses in the livestock sector. To understand the distribution and drug resistance characteristics of S. agalactiae from dairy cow mastitis cases in China, multilocus sequence typing (MLST) was carried out and the serotypes and drug resistance characteristics of the bacteria in the region were analysed.


Material and Methods
A total of 21 strains of bovine S. agalactiae were characterised based on MLST, molecular serotyping, antimicrobial susceptibility testing, and the presence of drug resistance genes.


Results
The serotypes were mainly Ia and II, accounting for 47.6% and 42.9% of all serotypes, respectively. Five sequence types (STs) were identified through MLST. The ST103 and ST1878 strains were predominant, with rates of 52.4% and 28.6%, respectively. The latter is a novel, previously uncharacterised sequence type. More than 90% of S. agalactiae strains were susceptible to penicillin, oxacillin, cephalothin, ceftiofur, gentamicin, florfenicol and sulfamethoxazole. The bacteria showed high resistance to tetracycline (85.7%), clindamycin (52.1%) and erythromycin (47.6%). Resistant genes were detected by PCR, the result of which showed that 47.6%, 33.3% and 38.1% of isolates carried the tet(M), tet(O) and erm(B) genes, respectively.


Conclusion
The results of this study indicate that S. agalactiae show a high level of antimicrobial resistance. It is necessary to monitor the pathogens of mastitis to prevent the transmission of these bacteria.

Molecular characterisation and antimicrobial resistance of <italic>Streptococcus agalactiae</italic> isolates from dairy farms in China

Journal of Veterinary Research

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

Molecular characterisation and antimicrobial resistance of  isolates from dairy farms in China

Introduction
Streptococcus agalactiae (S. agalactiae) is a pathogen causing bovine mastitis that results in considerable economic losses in the livestock...

Molecular characterisation and antimicrobial resistance of Streptococcus agalactiae isolates from dairy farms in China

Publicado en línea: 16 jun 2023

Páginas: 161 - 167

Recibido: 23 dic 2022

Aceptado: 25 abr 2023

DOI: https://doi.org/10.2478/jvetres-2023-0027

Palabras clave
serotype, molecular characterisation, antimicrobial resistance, drug resistance gene

© 2023 Xiaojiao Ma et al., published by Sciendo

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

Molecular characterisation and antimicrobial resistance of Streptococcus agalactiae isolates from dairy farms in China

Publicado en línea: 16 jun 2023

Páginas: 161 - 167

Recibido: 23 dic 2022

Aceptado: 25 abr 2023

DOI: https://doi.org/10.2478/jvetres-2023-0027

Palabras claveserotype, molecular characterisation, antimicrobial resistance, drug resistance gene

© 2023 Xiaojiao Ma et al., published by Sciendo

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

Palabras clave
serotype, molecular characterisation, antimicrobial resistance, drug resistance gene