Pathogenicity and virulence of Rhodococcus equi in foals following intratracheal challenge.
Abstract: Twelve foals, between 27 and 83 days old, were infected with 2 strains of Rhodococcus equi by intratracheal administration. Ten of the 12 foals were inoculated with 10(4)-10(10) colony forming units (cfu) of ATCC 33701 strain. The other 2 foals were inoculated with 10(9) cfu of a plasmid-cured derivative of the ATCC 33701 strain (ATCC 33701P-). All of the 10 foals challenged with the ATCC 33701 strain showed clinical signs of pulmonary disease within 5-13 days, such as gross lesions associated with acute bronchopneumonia and microscopic lesions associated with granulomatous pneumonia. The two foals challenged with the ATCC 33701P- strain showed neither clinical signs of disease nor gross lesions. Apparently, when lacking plasmid, the virulent Rhodococcus equi lost its pathogenicity.
Publication Date: 1997-06-16 PubMed ID: 9226844DOI: 10.1016/s0378-1135(97)00098-9Google Scholar: Lookup
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- Comparative Study
- Journal Article
Summary
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This research paper focuses on the investigation of the pathogenicity and virulence of two strains of Rhodococcus equi in foals, which found that one strain causes disease symptoms while a variant lacking a certain plasmid does not.
Methodology
- The team of researchers conducted an experiment involving twelve young foals between 27 and 83 days of age. The foals were infected through an intratracheal administration, which involves inserting a tube into the trachea to administer the bacteria.
- Out of the twelve foals, ten were inoculated with 10(4)-10(10) colony-forming units (cfu) of the ATCC 33701 strain of Rhodococcus equi. The remaining two foals were administered with 10(9) cfu of a plasmid-cured version of the ATCC 33701 strain, labeled as ATCC 33701P-.
Results
- The ten foals that received the standard ATCC 33701 strain displayed clinical symptoms of pulmonary disease between 5 to 13 days after infection. The symptoms included serious bronchopneumonia lesions and microscopic lesions linked to granulomatous pneumonia.
- The two foals infected with the ATCC 33701P- strain that lack the plasmid showed no clinical symptoms or gross lesions. Therefore, the research highlights that there is a consequential relationship between the presence of the plasmid in the Rhodococcus equi bacteria and its ability to cause disease.
Conclusion
- The study’s outcomes suggest that the plasmid found in the ATCC 33701 strain of Rhodococcus equi plays a crucial role in the pathogenicity and virulence of the bacteria. When the bacteria lacks this plasmid, it loses its capacity to cause disease, as indicated by the unaffected state of the two foals that were infected with the plasmid-free strain.
- This discovery helps illustrate how certain genetic elements of bacteria, such as plasmids, can significantly affect their ability to cause disease, and could be critical in developing more effective treatments or preventative measures against infections caused by Rhodococcus equi.
Cite This Article
APA
Wada R, Kamada M, Anzai T, Nakanishi A, Kanemaru T, Takai S, Tsubaki S.
(1997).
Pathogenicity and virulence of Rhodococcus equi in foals following intratracheal challenge.
Vet Microbiol, 56(3-4), 301-312.
https://doi.org/10.1016/s0378-1135(97)00098-9 Publication
Researcher Affiliations
- Epizootic Research Station, Equine Research Institute, Japan Racing Association, Tochigi, Japan. wada@epizoo.equinst.go.jp
MeSH Terms
- Actinomycetales Infections / pathology
- Actinomycetales Infections / physiopathology
- Actinomycetales Infections / veterinary
- Animals
- Body Temperature
- Granuloma / microbiology
- Granuloma / pathology
- Granuloma / veterinary
- Horse Diseases
- Horses
- Lung / microbiology
- Lung / pathology
- Lung Diseases / microbiology
- Lung Diseases / pathology
- Lung Diseases / veterinary
- Macrophages / microbiology
- Pneumonia, Bacterial / pathology
- Pneumonia, Bacterial / physiopathology
- Pneumonia, Bacterial / veterinary
- Rhodococcus equi / classification
- Rhodococcus equi / isolation & purification
- Rhodococcus equi / pathogenicity
- Species Specificity
- Time Factors
- Trachea
- Virulence
Citations
This article has been cited 23 times.- Cohen ND, Kahn SK, Bordin AI, Gonzales GM, da Silveira BP, Bray JM, Legere RM, Ramirez-Cortez SC. Association of pneumonia with concentrations of virulent Rhodococcus equi in fecal swabs of foals before and after intrabronchial infection with virulent R. equi. J Vet Intern Med 2022 May;36(3):1139-1145.
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