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Veterinary microbiology2019; 235; 243-247; doi: 10.1016/j.vetmic.2019.07.010

Prevalence and risk factors associated with emergence of Rhodococcus equi resistance to macrolides and rifampicin in horse-breeding farms in Kentucky, USA.

Abstract: The combination of a macrolide and rifampicin has been the mainstay of therapy in foals with Rhodococcus equi pneumonia for decades. Recent studies suggest that mass antimicrobial treatment of subclinically affected foals over time has selected for antimicrobial resistance. Our objective was to estimate the prevalence of R. equi strains resistant to macrolides and rifampicin at horse breeding farms in Kentucky. A hundred breeding farms in Kentucky were surveyed and R. equi were cultured from soil samples. Data were analyzed with logistic regression and generalized linear modeling (P < 0.05). Seventy-six percent (76%) of farms yielded resistant R. equi, and resistance to macrolides and rifampicin was associated with their use at farms. The present study is the first to report the prevalence and distribution of resistant isolates in the environment of farms in Kentucky, USA. Collectively, previous reports and the data presented herein provide irrefutable evidence of emerging antimicrobial resistance in R. equi with alarming prevalence. Widespread dissemination and maintenance of resistance genes in the environment where many other pathogenic bacteria exist is a concern for both animal and human health.
Copyright © 2019 Elsevier B.V. All rights reserved.
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Publication Date: 2019-07-10 PubMed ID: 31383308DOI: 10.1016/j.vetmic.2019.07.010Google Scholar: Lookup
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  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

This research investigates the prevalence and risk factors related to drug resistance in Rhodococcus equi, a bacteria causing pneumonia in foals, on horse breeding farms in Kentucky. It found 76% of surveyed farms had drug-resistant R. equi and its presence was linked to farms using antibiotics macrolides and rifampicin.

Objective of the Study

  • The primary goal of the study was to estimate the prevalence of Rhodococcus equi strains resistant to two types of antibiotics: macrolides and rifampicin. Rhodococcus equi is a bacterium causing pneumonia in foals (young horses).
  • Furthermore, the research aimed to provide insight into emerging antimicrobial resistance which is of growing concerns in both human and animal healthcare.

Methodology

  • For the study, 100 horse breeding farms in Kentucky, USA were surveyed.
  • R. equi samples were cultured from soil samples collected from these farms.
  • The research data was then analyzed using logistics regression and generalized linear modeling with a <0.05 significance level.

Study Findings

  • The appeared that a staggering 76% of the sampled farms had instances of R. equi which were resistant to macrolides and rifampicin.
  • The usage of macrolides and rifampicin was found to have a direct association with the emergence of such resistant strains of the bacteria.

Significance and Implications of the Study

  • The study offers the first report detailing the prevalence and distribution of antibiotic-resistant strains of R. equi in the environmental setting of horse farms in Kentucky.
  • Emerging antimicrobial resistance is a major concern for both human and animal health. The fact that resistant strains of R. equi were found in areas where many other pathogenic bacteria could exist is alarming, suggesting that resistance genes could potentially spread to other bacteria.
  • The findings hint towards the need for more responsible and judicious use of antibiotics in veterinary contexts to help curb the surge of drug-resistant strains of harmful bacteria.

Cite This Article

APA
Huber L, Giguère S, Cohen ND, Slovis NM, Hanafi A, Schuckert A, Berghaus L, Greiter M, Hart KA. (2019). Prevalence and risk factors associated with emergence of Rhodococcus equi resistance to macrolides and rifampicin in horse-breeding farms in Kentucky, USA. Vet Microbiol, 235, 243-247. https://doi.org/10.1016/j.vetmic.2019.07.010

Publication

Veterinary microbiology
ISSN: 1873-2542
NlmUniqueID: 7705469
Country: Netherlands
Language: English
Volume: 235
Pages: 243-247
PII: S0378-1135(19)30625-X

Researcher Affiliations

Huber, Laura
  • Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA, USA.
Giguère, Steeve
  • Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA, USA.
Cohen, Noah D
  • Department of Large Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX, USA. Electronic address: ncohen@cvm.tamu.edu.
Slovis, Nathan M
  • Hagyard Equine Medical Institute, Lexington, KY, USA.
Hanafi, Amanda
  • Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA, USA.
Schuckert, Amanda
  • Department of Large Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX, USA.
Berghaus, Londa
  • Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA, USA.
Greiter, Maggie
  • Hagyard Equine Medical Institute, Lexington, KY, USA.
Hart, Kelsey A
  • Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA, USA.

MeSH Terms

  • Actinomycetales Infections / veterinary
  • Animals
  • Anti-Bacterial Agents / pharmacology
  • Breeding
  • Drug Resistance, Multiple, Bacterial / genetics
  • Farms
  • Horse Diseases / epidemiology
  • Horse Diseases / microbiology
  • Horses
  • Kentucky / epidemiology
  • Macrolides / pharmacology
  • Prevalence
  • Rhodococcus equi / drug effects
  • Rhodococcus equi / genetics
  • Rifampin / pharmacology
  • Risk Factors

Citations

This article has been cited 18 times.
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