Ecology of Rhodococcus equi.
Abstract: A selective broth enrichment technique was used to study the distribution of Rhodococcus equi in soil and grazing animals. Rhodococcus equi was isolated from 54% of soils examined and from the gut contents, rectal faeces and dung of all grazing herbivorous species examined. Rhodococcus equi was not isolated from the faeces or dung of penned animals which did not have access to grazing. The isolation rate from dung was much higher than from other samples and this was found to be due to the ability of R. equi to multiply more readily in dung. Delayed hypersensitivity tests were carried out on horses, sheep and cattle, but only horses reacted significantly. The physiological characteristics of R. equi and the nature of its distribution in the environment suggested that R. equi is a soil organism.
Publication Date: 1984-02-01 PubMed ID: 6719819DOI: 10.1016/0378-1135(84)90079-8Google Scholar: Lookup
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- Journal Article
Summary
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This research investigates the presence of bacterium Rhodococcus equi in soils and grazing animals using a selective broth enrichment technique, establishing the bacterium as a soil organism, influencing horses primarily.
Methodology and Findings
- The study utilized a selective broth enrichment technique to determine the distribution of Rhodococcus equi, a bacterium of considerable significance in equine medicine, in various environments and hosts.
- More than half of the soils that they analyzed (54%) contained Rhodococcus equi. This points towards the prominence of the bacterium in the soil environment.
- Furthermore, the research team found Rhodococcus equi in the gut contents, rectal faeces, and dung of all grazing herbivorous species they inspected. This suggests that this bacterium is part of the normal gut flora for these animals, particularly when they are grazing.
- In contrast, Rhodococcus equi was absent in penned animals without access to pastures for grazing. This indicates that the bacterium’s prevalence in animals could be directly linked to their exposure to soil and grass, reiterating its status as a soil organism.
Significance of Dung in Bacteria Multiplication
- The researchers identified that the bacterium multiplies more prolifically in dung, explaining the higher rate of isolation in these samples compared to others.
- This suggests that dung forms an ideal environment for bacterial propagation. When passed out and mixed with soil, dung might help in preserving and multiplying the bacterium in the environment, thus contributing to its endemicity in soils.
Host Reactivity
- The team conducted delayed hypersensitivity tests, an immune response test, on horses, sheep, and cattle. The results showed that only horses reacted notably, implying that they might be more susceptible to infections caused by this bacterium.
- This information can be crucial for veterinary medicine, particularly concerning horses’ health and any potential interventions in managing Rhodococcus equi-related diseases.
Understanding the Nature of R. equi
- Based on R. equi’s physiological characteristics and distribution patterns observed in this study, the researchers concluded that R. equi is a soil organism.
- This finding adds value to our understanding of this bacterium’s ecology and helps devise better strategies for its management and control, particularly in settings where it may pose a threat to the health of grazing animals, especially horses.
Cite This Article
APA
Barton MD, Hughes KL.
(1984).
Ecology of Rhodococcus equi.
Vet Microbiol, 9(1), 65-76.
https://doi.org/10.1016/0378-1135(84)90079-8 Publication
Researcher Affiliations
MeSH Terms
- Actinomycetales / growth & development
- Actinomycetales / immunology
- Actinomycetales / isolation & purification
- Animal Husbandry
- Animals
- Antigens, Bacterial / immunology
- Artiodactyla / microbiology
- Australia
- Digestive System / microbiology
- Ecology
- Feces / microbiology
- Horses / microbiology
- Hypersensitivity, Delayed
- Rabbits / microbiology
- Soil Microbiology
Citations
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