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The Veterinary record2023; 192(5); e2591; doi: 10.1002/vetr.2591

Antimicrobial resistance of endometrial bacterial isolates collected from UK Thoroughbred mares between 2014 and 2020.

Abstract: Antimicrobial resistance (AMR) is important in equine reproduction, as antimicrobials have historically been widely used in the management of breeding mares. However, evidence of the characteristics of AMR in uterine isolates is limited in the UK. The objective of this retrospective study was therefore to describe temporal changes in AMR patterns of bacteria isolated from the endometrium of Thoroughbred broodmares in south-east England between 2014 and 2020. Endometrial swabs were processed for microbiology and antimicrobial susceptibility testing (AST). For frequently isolated bacteria, changes in AMR patterns over time were assessed using a logistic regression model. From 18,996 endometrial swabs, 30.5% were positive for microbial culture. AST was performed on 2091 isolates, representing 1924 swabs collected from 1370 mares located at 132 premises. Beta-haemolytic Streptococcus (BHS, 52.5%) and Escherichia coli (25.8%) were most frequently isolated. In BHS, resistance to enrofloxacin (p = 0.02), nitrofurazone (p < 0.001) and oxytetracycline (p < 0.01) increased significantly between 2014 and 2020, while resistance to trimethoprim-sulfamethoxazole (p < 0.001) decreased. In E. coli, resistance to nitrofurazone increased (p = 0.04) and resistance to gentamycin (p = 0.02) and trimethoprim-sulfamethoxazole (p < 0.001) decreased. Variations in the specimen collection protocols might have affected the frequency of isolates detected. Between 2014 and 2020, AMR changed in this bacterial population. However, there was no significant increase in resistance to penicillin (99.6% BHS susceptible), gentamycin (81.7% E. coli susceptible) or ceftiofur.
© 2023 British Veterinary Association.
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Publication Date: 2023-02-21 PubMed ID: 36809533DOI: 10.1002/vetr.2591Google Scholar: Lookup
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  • Journal Article

Summary

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This research paper analyzes the changing patterns of antimicrobial resistance in bacteria found in the endometrium of Thoroughbred broodmares in the UK from 2014 to 2020. It has discovered an increasing resistance to certain antibiotics in Beta-haemolytic Streptococcus and Escherichia coli, two bacteria often found in these horses.

Study Objective and Methods

  • The main objective of the research was to describe the changes in antimicrobial resistance (AMR) in bacteria isolated from the endometrium of Thoroughbred mares over a six-year period
  • Endometrial swabs were collected for microbiological analysis and antimicrobial susceptibility testing (AST)
  • The investigation focused primarily on the bacteria isolated most frequently, using a logistic regression model to track the changes in AMR over time

Results and Findings

  • A significant amount of the swabs – 30.5% – tested positive for microbial culture
  • A total of 2091 isolates, collected from 1924 swabs from 1370 mares across 132 premises, underwent antimicrobial susceptibility testing
  • The most frequently isolated bacteria were Beta-haemolytic Streptococcus (52.5%) and Escherichia coli (25.8%)
  • For Beta-haemolytic Streptococcus, resistance to three antibiotics – enrofloxacin, nitrofurazone, and oxytetracycline – showed a significant increase from 2014 to 2020
  • However, its resistance to trimethoprim-sulfamethoxazole decreased within the same period
  • Escherichia coli resistance to nitrofurazone also increased, while its resistance to gentamycin and trimethoprim-sulfamethoxazole decreased

Conclusions

  • Variations in specimen collection methodology may have influenced the frequency of bacterial isolates detected
  • Study findings indicate clear changes in AMR of the bacterial population between 2014 and 2020, with certain antibiotics demonstrating less efficiency in battling these strains
  • However, there was no significant increase in resistance to penicillin, gentamycin, or ceftiofur, as 99.6% of Beta-haemolytic Streptococcus remain susceptible to penicillin, and 81.7% of Escherichia coli are susceptible to gentamycin

Cite This Article

APA
Rathbone P, Arango-Sabogal JC, De Mestre AM, Scott CJ. (2023). Antimicrobial resistance of endometrial bacterial isolates collected from UK Thoroughbred mares between 2014 and 2020. Vet Rec, 192(5), e2591. https://doi.org/10.1002/vetr.2591

Publication

The Veterinary record
ISSN: 2042-7670
NlmUniqueID: 0031164
Country: England
Language: English
Volume: 192
Issue: 5
Pages: e2591

Researcher Affiliations

Rathbone, Polly
  • Department of Comparative Biomedical Sciences, Royal Veterinary College, Hatfield, UK.
Arango-Sabogal, Juan C
  • Department of Pathobiology and Population Sciences, Royal Veterinary College, Hatfield, UK.
  • Département de Pathologie et Microbiologie, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Q, Canada.
De Mestre, Amanda M
  • Department of Comparative Biomedical Sciences, Royal Veterinary College, Hatfield, UK.
Scott, Camilla J
  • Rossdales Veterinary Surgeons, Newmarket, UK.

MeSH Terms

  • Animals
  • Horses
  • Female
  • Anti-Bacterial Agents / pharmacology
  • Escherichia coli
  • Trimethoprim, Sulfamethoxazole Drug Combination
  • Nitrofurazone
  • Retrospective Studies
  • Drug Resistance, Bacterial
  • Bacteria
  • Gentamicins
  • Endometrium
  • Microbial Sensitivity Tests / veterinary
  • United Kingdom

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Citations

This article has been cited 7 times.
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  2. Fehin B, Scott CJ, Arango-Sabogal JC, de Mestre AM, Mouncey R. Associations between endometrial swab bacteriology and cytology findings and live foal rates in Thoroughbred broodmares in the United Kingdom. Equine Vet J 2026 Mar;58(2):348-358.
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