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Home / Equine Research Bank / Appl Environ Microbiol / Associations between the ecology of virulent Rhodococcus equ...
Applied and environmental microbiology2006; 72(9); 6152-6160; doi: 10.1128/AEM.00495-06

Associations between the ecology of virulent Rhodococcus equi and the epidemiology of R. equi pneumonia on Australian thoroughbred farms.

Abstract: The ecology of virulent strains of Rhodococcus equi on horse farms is likely to influence the prevalence and severity of R. equi pneumonia in foals. This study examined the association between the ecology of virulent R. equi and the epidemiology of R. equi pneumonia by collecting air and soil samples over two breeding seasons (28 farm-year combinations) on Thoroughbred breeding farms with different reported prevalences of R. equi pneumonia. Colony blotting and DNA hybridization were used to detect and measure concentrations of virulent R. equi. The prevalence of R. equi pneumonia was associated with the airborne burden of virulent R. equi (both the concentration and the proportion of R. equi bacteria that were virulent) but was not associated with the burden of virulent R. equi in the soil. Univariable screening and multivariable model building were used to evaluate the effect of environmental and management factors on virulent R. equi burdens. Lower soil moisture concentrations and lower pasture heights were significantly associated with elevated airborne concentrations of virulent R. equi, as were the holding pens and lanes, which typically were sandy, dry, and devoid of pasture cover. Few variables appeared to influence concentrations of virulent R. equi in soil. Acidic soil conditions may have contributed to an elevated proportion of virulent strains within the R. equi population. Environmental management strategies that aim to reduce the level of exposure of susceptible foals to airborne virulent R. equi are most likely to reduce the impact of R. equi pneumonia on endemically affected farms.
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Publication Date: 2006-09-08 PubMed ID: 16957241PubMed Central: PMC1563629DOI: 10.1128/AEM.00495-06Google Scholar: Lookup
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  • Journal Article
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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.

The research article investigates how the ecological conditions of virulent strains of Rhodococcus equi, a bacterium responsible for pneumonia in foals, specifically impact its prevalence and severity on Australian thoroughbred farms.

Research Methodology and Approach

  • The study analyses the relationship between the ecology of virulent R. equi and the epidemiology of R. equi pneumonia. This was done by collecting and analyzing air and soil samples over two breeding seasons frommultiple thoroughbred breeding farms that had different reported prevalences of R. equi pneumonia.
  • Technical methods like colony blotting and DNA hybridization were employed in order to detect and measure the concentrations of the virulent R. equi.

Findings and Associations

  • The observed prevalence of R. equi pneumonia was associated with the airborne concentration and proportion of R. equi bacteria. However, it showed no significant association with the burden of virulent R. equi present in the soil.
  • Other environmental factors such as lower soil moisture concentrations, lower pasture heights, and certain farm infrastructure like holding pens and lanes (commonly sandy, dry, and devoid of pasture cover) were found to be significantly associated with higher airborne concentrations of virulent R. equi.
  • Acidic soil conditions may indirectly be contributing to the problem by increasing the proportion of virulent strains within the R. equi population.

Implications and Recommendations

  • As a main discovery of the research, the study suggests focusing on environmental management strategies that aim to reduce the level of exposure of susceptible foals to airborne virulent R. equi.
  • By focusing on the factors in the environment that increase the airborne concentration of the bacteria, it could be possible to minimize the impact of R. equi pneumonia on farms that are affected on a regular basis.

Cite This Article

APA
Muscatello G, Anderson GA, Gilkerson JR, Browning GF. (2006). Associations between the ecology of virulent Rhodococcus equi and the epidemiology of R. equi pneumonia on Australian thoroughbred farms. Appl Environ Microbiol, 72(9), 6152-6160. https://doi.org/10.1128/AEM.00495-06

Publication

Applied and environmental microbiology
ISSN: 0099-2240
NlmUniqueID: 7605801
Country: United States
Language: English
Volume: 72
Issue: 9
Pages: 6152-6160

Researcher Affiliations

Muscatello, G
  • School of Veterinary Science, The University of Melbourne, Parkville, Victoria 3010, Australia. mug@unimelb.edu.au
Anderson, G A
    Gilkerson, J R
      Browning, G F

        MeSH Terms

        • Actinomycetales Infections / epidemiology
        • Actinomycetales Infections / microbiology
        • Actinomycetales Infections / veterinary
        • Air Microbiology
        • Animal Husbandry
        • Animals
        • Animals, Newborn
        • Australia / epidemiology
        • Colony Count, Microbial
        • DNA, Bacterial / genetics
        • Ecosystem
        • Horse Diseases / epidemiology
        • Horse Diseases / microbiology
        • Horses
        • Pneumonia, Bacterial / epidemiology
        • Pneumonia, Bacterial / microbiology
        • Pneumonia, Bacterial / veterinary
        • Rhodococcus equi / genetics
        • Rhodococcus equi / isolation & purification
        • Rhodococcus equi / pathogenicity
        • Soil Microbiology
        • Virulence

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