Cholesterol oxidase (ChoE) is not important in the virulence of Rhodococcus equi.
Abstract: To analyze further the role in virulence of the prominent cholesterol oxidase (ChoE) of Rhodococcus equi, an allelic exchange choE mutant from strain 103+ was constructed and assessed for virulence in macrophages, in mice, and in foals. There was no difference between the mutant and parent strain in cytotoxic activity for macrophages or in intra-macrophage multiplication. No evidence of attenuation was obtained in macrophages and in mice, but there was slight attenuation apparent in four intra-bronchially infected foals compared to infection of four foals with the virulent parent strain, based on a delayed rise in temperature of the choE-mutant infected foals. However, bacterial colony counts in the lung 2 weeks after infection were not significantly different, although there was a slight but non-significant (P=0.12) difference in lung:body weight ratio of the choE mutant versus virulent parent infected foals (mean 2.67+/-0.25% compared to 4.58+/-0.96%). We conclude that the cholesterol oxidase is not important for the virulence of R. equi.
Publication Date: 2006-08-14 PubMed ID: 16979852DOI: 10.1016/j.vetmic.2006.08.006Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research conducted concludes that the cholesterol oxidase, ChoE, is not significant in the virulence, or harm causing ability, of the bacteria Rhodococcus equi.
Study Methodology
- The study analyzed the role in virulence of cholesterol oxidase (ChoE) of Rhodococcus equi, a bacterium responsible for bacterial infections in livestock and immunocompromised individuals.
- The researchers created a choE mutant strain from a parent strain to test the infectivity and virulence of this altered form of the bacteria.
- The choE mutant was then tested for virulence using three separate organisms as models: macrophages (immune cells that engulf bacteria), mice, and foals (young horses).
Results and Observations
- The researchers observed no difference in cytotoxic activity (the ability to kill cells) or multiplication within macrophages between the choE mutant and the parent strain.
- No evidence of reduced virulence (attenuation) was observed in macrophages and mice infected with the choE mutant strain.
- However, a slight attenuation was observed in foals infected with the choE mutant strain. The evidence for this was a delayed rise in temperature compared to foals infected with the parent strain.
- Importantly, bacterial colony counts in the lung tissue of the foals two weeks post-infection showed no significant difference between the two groups.
- A slight but non-significant difference was observed in the lung-to-body weight ratio of foals infected with the choE mutant versus the parent strain.
Conclusion
- The study concludes that cholesterol oxidase, encoded by the gene choE, is not a major factor in the virulence of Rhodococcus equi. Its mutation does not notably alter the ability of this bacterium to infect and cause disease in tested entities.
- This insight could have implications for studies targeting this bacterium and its virulence factors for treatments or preventive measures in livestock and humans.
Cite This Article
APA
Pei Y, Dupont C, Sydor T, Haas A, Prescott JF.
(2006).
Cholesterol oxidase (ChoE) is not important in the virulence of Rhodococcus equi.
Vet Microbiol, 118(3-4), 240-246.
https://doi.org/10.1016/j.vetmic.2006.08.006 Publication
Researcher Affiliations
- Department of Pathobiology, University of Guelph, Guelph, Ontario, Canada.
MeSH Terms
- Actinomycetales Infections / microbiology
- Actinomycetales Infections / veterinary
- Animals
- Cholesterol Oxidase / genetics
- Cholesterol Oxidase / metabolism
- Female
- Horse Diseases / microbiology
- Horses
- Macrophages / microbiology
- Mice
- Mice, Inbred Strains
- Rhodococcus equi / enzymology
- Rhodococcus equi / genetics
- Rhodococcus equi / pathogenicity
- Time Factors
- Virulence / genetics
Citations
This article has been cited 8 times.- Sydor T, von Bargen K, Hsu FF, Huth G, Holst O, Wohlmann J, Becken U, Dykstra T, Söhl K, Lindner B, Prescott JF, Schaible UE, Utermöhlen O, Haas A. Diversion of phagosome trafficking by pathogenic Rhodococcus equi depends on mycolic acid chain length. Cell Microbiol 2013 Mar;15(3):458-73.
- García JL, Uhía I, Galán B. Catabolism and biotechnological applications of cholesterol degrading bacteria. Microb Biotechnol 2012 Nov;5(6):679-99.
- van der Geize R, Grommen AW, Hessels GI, Jacobs AA, Dijkhuizen L. The steroid catabolic pathway of the intracellular pathogen Rhodococcus equi is important for pathogenesis and a target for vaccine development. PLoS Pathog 2011 Aug;7(8):e1002181.
- Kreit J, Sampson NS. Cholesterol oxidase: physiological functions. FEBS J 2009 Dec;276(23):6844-56.
- Monego F, Maboni F, Krewer C, Vargas A, Costa M, Loreto E. Molecular characterization of Rhodococcus equi from horse-breeding farms by means of multiplex PCR for the vap gene family. Curr Microbiol 2009 Apr;58(4):399-403.
- van der Geize R, de Jong W, Hessels GI, Grommen AW, Jacobs AA, Dijkhuizen L. A novel method to generate unmarked gene deletions in the intracellular pathogen Rhodococcus equi using 5-fluorocytosine conditional lethality. Nucleic Acids Res 2008 Dec;36(22):e151.
- Piubelli L, Pedotti M, Molla G, Feindler-Boeckh S, Ghisla S, Pilone MS, Pollegioni L. On the oxygen reactivity of flavoprotein oxidases: an oxygen access tunnel and gate in brevibacterium sterolicum cholesterol oxidase. J Biol Chem 2008 Sep 5;283(36):24738-47.
- Lyubimov AY, Heard K, Tang H, Sampson NS, Vrielink A. Distortion of flavin geometry is linked to ligand binding in cholesterol oxidase. Protein Sci 2007 Dec;16(12):2647-56.
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