Antimicrobial-Resistant Enterococcus faecium and Enterococcus faecalis Isolated From Healthy Thoroughbred Racehorses in Japan.
Abstract: In this study, the occurrence of antimicrobial-resistant (AMR) enterococci was evaluated in Thoroughbred (TB) racehorses in Japan. Fecal samples were collected from 212 healthy TB racehorses at the Miho and Ritto Training Centers of the Japan Racing Association from March 2017 to August 2018. Isolation and identification were performed by enterococcus selective medium and confirmed to the species using MALDI-TOF MS. Enterococcus faecium and E. faecalis isolates were subjected to antimicrobial susceptibility test against 11 antimicrobials by minimum inhibitory concentration based on recommendation from Clinical and Laboratory Standards Institute guidelines. Among 583 enterococcus isolates, E. faecium and E. faecalis were identified for 48.2% (281/583) and 7.4% (43/583), respectively. One isolate that was representing E. faecium (153 isolates) and E. faecalis (31 isolates) from each sample was selected for antimicrobial susceptibility test. The highest rate of resistance for E. faecium isolates was observed against enrofloxacin (57.5%; 88/153), followed by streptomycin (32.0%; 49/153), kanamycin (18.3%; 28/153), gentamycin (5.9%; 9/153), erythromycin (5.9%; 9/153), and oxytetracycline (4.6%; 7/153). For E. faecium isolates, the highest resistance was observed against streptomycin (90.3%; 28/31), followed by kanamycin (41.9%; 13/31), gentamycin (29.0%; 9/31), lincomycin (9.7%; 3/31), oxytetracycline (6.5%; 2/31), erythromycin (6.5%; 2/31), tylosin (6.5%; 2/31), enrofloxacin (6.5%; 2/31), and chloramphenicol (3.2%; 1/31). The results indicated that enrofloxacin and aminoglycosides were highly resistant among tested antimicrobials. Continuous monitoring studies are useful to increase the awareness of the potential for AMR bacteria to arise from imprudent use of antimicrobials in TB racehorses in Japan.
Copyright © 2020 Elsevier Inc. All rights reserved.
Publication Date: 2020-08-25 PubMed ID: 33077095DOI: 10.1016/j.jevs.2020.103232Google Scholar: Lookup
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- Journal Article
Summary
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The study analyzed samples from thoroughbred racehorses in Japan and found a significant number of isolates of antimicrobial-resistant Enterococcus faecium and Enterococcus faecalis. It suggests that increased monitoring of these bacteria could help raise awareness of the dangers of imprudent use of antimicrobials.
Research Methodology
- Fecal samples were collected from 212 healthy Thoroughbred (TB) racehorses at the Miho and Ritto Training Centers of the Japan Racing Association.
- The timeframe of the study was from March 2017 to August 2018.
- The isolation and identification of the bacteria were carried out using an enterococcus selective medium.
- Identification of the bacteria species used MALDI-TOF MS.
- The E. faecium and E. faecalis isolates were tested for their susceptibility to 11 antimicrobials. They used the minimum inhibitory concentration method, which follows the guidelines of the Clinical and Laboratory Standards Institute.
Key Findings
- A total of 583 enterococcus isolates were identified, with 48.2% (281 out of 583) being E. faecium and 7.4% (43 out of 583) E. faecalis.
- For E. faecium isolates, the highest rate of resistance was found against enrofloxacin (57.5%), followed by streptomycin, kanamycin, gentamycin, erythromycin, and oxytetracycline.
- High resistance among E. faecalis isolates was seen against streptomycin (90.3%), followed by kanamycin, gentamycin, lincomycin, oxytetracycline, erythromycin, tylosin, enrofloxacin, and chloramphenicol.
Implications of the Findings
- The study found high levels of antimicrobial resistance among the tested microbes.
- The two antibiotics that the bacteria were exceptionally resistant to were enrofloxacin and aminoglycosides.
- The findings highlighted the dangers that can stem from the imprudent use of antimicrobials, implying that restrictive use of these substances might reduce antimicrobial resistance.
- The results also suggest that continuous monitoring studies are necessary to broaden understanding and awareness of the potential risks of antimicrobial-resistant bacteria arising in racehorses in Japan.
Cite This Article
APA
Sukmawinata E, Sato W, Uemura R, Kanda T, Kusano K, Kambayashi Y, Sato T, Ishikawa Y, Toya R, Sueyoshi M.
(2020).
Antimicrobial-Resistant Enterococcus faecium and Enterococcus faecalis Isolated From Healthy Thoroughbred Racehorses in Japan.
J Equine Vet Sci, 94, 103232.
https://doi.org/10.1016/j.jevs.2020.103232 Publication
Researcher Affiliations
- Graduate School of Medicine and Veterinary Medicine, University of Miyazaki, Miyazaki, Japan.
- Department of Veterinary Sciences, Faculty of Agriculture, University of Miyazaki, Miyazaki, Japan.
- Department of Veterinary Sciences, Faculty of Agriculture, University of Miyazaki, Miyazaki, Japan; Center for Animal Diseases Control, University of Miyazaki, Miyazaki, Japan. Electronic address: uemurary@cc.miyazaki-u.ac.jp.
- Graduate School of Medicine and Veterinary Medicine, University of Miyazaki, Miyazaki, Japan.
- Miho Training Center, Racehorse Clinic, Japan Racing Association, Ibaraki, Japan.
- Miho Training Center, Racehorse Clinic, Japan Racing Association, Ibaraki, Japan.
- Ritto Training Center, Racehorse Clinic, Japan Racing Association, Shiga, Japan.
- Ritto Training Center, Racehorse Clinic, Japan Racing Association, Shiga, Japan.
- Graduate School of Medicine and Veterinary Medicine, University of Miyazaki, Miyazaki, Japan.
- Graduate School of Medicine and Veterinary Medicine, University of Miyazaki, Miyazaki, Japan; Department of Veterinary Sciences, Faculty of Agriculture, University of Miyazaki, Miyazaki, Japan.
MeSH Terms
- Animals
- Anti-Bacterial Agents / pharmacology
- Anti-Infective Agents
- Enterococcus faecalis
- Enterococcus faecium
- Horses
- Japan / epidemiology
Citations
This article has been cited 2 times.- Thompson JE. Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry in veterinary medicine: Recent advances (2019-present). Vet World 2022 Nov;15(11):2623-2657.
- Koleini M, Mosadegh A, Madadizadeh F, Heidari H. Assessment of Factors Contributing to Infection Severity and High Levels of Drug Resistance in Clinical Enterococcus Isolates. J Clin Lab Anal 2025 Jul;39(14):e70063.
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