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Antimicrobial agents and chemotherapy2018; 63(1); e01714-18; doi: 10.1128/AAC.01714-18

Emergence of Resistance to Macrolides and Rifampin in Clinical Isolates of Rhodococcus equi from Foals in Central Kentucky, 1995 to 2017.

Abstract: The objective of this study was to determine the prevalence of strains resistant to macrolides and rifampin over time in clinical samples from foals submitted to diagnostic laboratories in central Kentucky. We performed a retrospective observational study of all clinical samples from foals that were submitted to veterinary diagnostic laboratories in Kentucky between January 1995 and December 2017. Samples were included if the bacterium was cultured and tested for susceptibility to erythromycin or rifampin. susceptibility testing to erythromycin was available for 2,169 isolates of , while susceptibility testing to both erythromycin and rifampin was available for 1,681 isolates. Rifampin resistance was first detected in 2000, and erythromycin resistance was first detected in 2004. Between 1995 and 2006, the proportion of resistant isolates of was 0.7% for erythromycin and 2.3% for rifampin. There was a significant ( < 0.001) increase in the proportion of resistant between 2007 and 2017, with 13.6% of isolates being resistant to erythromycin and 16.1% being resistant to rifampin. Between 2007 and 2017, isolates of resistant to erythromycin or rifampin were significantly less likely to be isolated from feces than from the respiratory tract, other soft tissues, or musculoskeletal infections. The considerable increase in the prevalence of isolates of resistant to macrolides and rifampin since 2007 is of concern for both human and animal health.
Copyright © 2018 American Society for Microbiology.
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Publication Date: 2018-12-21 PubMed ID: 30373803PubMed Central: PMC6325176DOI: 10.1128/AAC.01714-18Google Scholar: Lookup
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  • Non-U.S. Gov't

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 article studies the increase in resistance to macrolides and rifampin in strains of Rhodococcus equi, a bacterium affecting foals, and found a significant increase in the prevalence of antibiotic resistance over a 22-year period in central Kentucky.

Research Objective and Methodology

  • The primary objective of this study was to examine how the prevalence of Rhodococcus equi strains resistant to macrolides and rifampin has increased over time.
  • To achieve this, the researchers conducted a retrospective observational study using clinical samples from foals, submitted to veterinary diagnostic laboratories in central Kentucky, between January 1995 and December 2017.
  • The samples were included if Rhodococcus equi bacterium was present and tested for susceptibility to either erythromycin (a macrolide) or rifampin.

Results and Analysis

  • Of the samples studied, susceptibility testing to erythromycin was available for 2,169 Rhodococcus equi isolates. Testing for both erythromycin and rifampin was available for 1,681 isolates.
  • Rifampin resistance was first detected in the year 2000, and erythromycin resistance was first detected in 2004.
  • Between 1995 and 2006, there was a low proportion of resistant isolates – 0.7% for erythromycin and 2.3% for rifampin.
  • A significant spike in antibiotic resistance occurred between 2007 and 2017, with 13.6% of isolates showing resistance to erythromycin and 16.1% showing resistance to rifampin.
  • Furthermore, isolates of Rhodococcus equi resistant to erythromycin or rifampin were significantly less likely to be isolated from feces compared to the respiratory tract, other soft tissues, or musculoskeletal infections between 2007 and 2017.

Conclusion and Implications

  • The study concluded that there’s a high rate of increase in the prevalence of Rhodococcus equi isolates, resistant to macrolides and rifampin, particularly after 2007.
  • This increase in antibiotic resistance is a cause of concern not just for the health of the animals, but it could potentially impact human health as well. Further research is likely needed to explore the possible reasons behind this drastic increase and to devise strategies to control and manage this threat.

Cite This Article

APA
Huber L, Giguère S, Slovis NM, Carter CN, Barr BS, Cohen ND, Elam J, Erol E, Locke SJ, Phillips ED, Smith JL. (2018). Emergence of Resistance to Macrolides and Rifampin in Clinical Isolates of Rhodococcus equi from Foals in Central Kentucky, 1995 to 2017. Antimicrob Agents Chemother, 63(1), e01714-18. https://doi.org/10.1128/AAC.01714-18

Publication

Antimicrobial agents and chemotherapy
ISSN: 1098-6596
NlmUniqueID: 0315061
Country: United States
Language: English
Volume: 63
Issue: 1
PII: e01714-18

Researcher Affiliations

Huber, Laura
  • Department of Large Animal Medicine, University of Georgia, Athens, Georgia, USA laura.huber16@hotmail.com.
Giguère, Steeve
  • Department of Large Animal Medicine, University of Georgia, Athens, Georgia, USA.
Slovis, Nathan M
  • Hagyard Equine Medical Institute, Lexington, Kentucky, USA.
Carter, Craig N
  • Veterinary Diagnostic Laboratory, University of Kentucky, Lexington, Kentucky, USA.
Barr, Bonnie S
  • Rood and Riddle Equine Hospital, Lexington, Kentucky, USA.
Cohen, Noah D
  • Department of Large Animal Clinical Sciences, Texas A&M University, College Station, Texas, USA.
Elam, Justine
  • Hagyard Equine Medical Institute, Lexington, Kentucky, USA.
Erol, Erdal
  • Veterinary Diagnostic Laboratory, University of Kentucky, Lexington, Kentucky, USA.
Locke, Stephan J
  • Veterinary Diagnostic Laboratory, University of Kentucky, Lexington, Kentucky, USA.
Phillips, Erica D
  • Veterinary Diagnostic Laboratory, University of Kentucky, Lexington, Kentucky, USA.
Smith, Jacqueline L
  • Veterinary Diagnostic Laboratory, University of Kentucky, Lexington, Kentucky, USA.

MeSH Terms

  • Actinomycetales Infections / drug therapy
  • Actinomycetales Infections / epidemiology
  • Actinomycetales Infections / microbiology
  • Actinomycetales Infections / veterinary
  • Animals
  • Anti-Bacterial Agents / pharmacology
  • Azithromycin / pharmacology
  • Clarithromycin / pharmacology
  • Drug Resistance, Multiple, Bacterial / drug effects
  • Drug Resistance, Multiple, Bacterial / genetics
  • Equidae
  • Erythromycin / pharmacology
  • Feces / microbiology
  • Horses
  • Kentucky / epidemiology
  • Microbial Sensitivity Tests
  • Musculoskeletal Diseases / drug therapy
  • Musculoskeletal Diseases / epidemiology
  • Musculoskeletal Diseases / microbiology
  • Musculoskeletal Diseases / veterinary
  • Prevalence
  • Respiratory System / drug effects
  • Respiratory System / microbiology
  • Rhodococcus equi / drug effects
  • Rhodococcus equi / genetics
  • Rhodococcus equi / growth & development
  • Rhodococcus equi / isolation & purification
  • Rifampin / pharmacology
  • Soft Tissue Infections / drug therapy
  • Soft Tissue Infections / epidemiology
  • Soft Tissue Infections / microbiology
  • Soft Tissue Infections / veterinary

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This article has been cited 25 times.
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