Felis ISSN 2398-2950


Synonym(s): Corynebacterium equi, C. equi, Rhodococcus equi, R. equi

Contributor(s): Susan Dawson, David Scarff




  • Genus: Corynebacterium.
  • Genus: Rhodococcus, formerly Corynebacterium.
  • Species :equi.


  • Gr: korune - club; bakterion - staff/cane/small rod.

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Clinical Effects



  • Corynebacterium spp in soil, feces and gastrointestinal tract of sheep, cattle, horses, etc.
  • Horses are the reservoir for R. equi, although it is also found in soil and other animals' feces.


  • Probably opportunistic infection in cats.
  • May follow trauma, other infections or immunosuppression.

Pathological effects

  • Probably opportunistic infections.
  • Localized abscesses or cellulitis.
  • R. equi and some Corynebacterium spp are facultative intracellular parasites.
  • Survive in macrophages via suppression of phagolysosomal fusion and evoking a pyogranulomatous response.
  • Survival in macrophages and induction of pyogranulomatous response   →   formation of abscesses and granulomas.
  • Lesions consist of macrophages and giant cells, plus neutrophils in caseous areas.
  • Corynebacterium spp have been isolated from plaque-like lesions and discharging sinuses.
  • R. equi has been cultured from occasional cases with cutaneous abscesses and cellulitis, and from mediastinal and mesenteric granulomas in an immunocompetent cat.

Other Host Effects

  • Significant feline infections are probably rare.


Control via animal

  • Surgical drainage of abscesses.

Control via chemotherapies

  • Antibiotic susceptibility testing recommended.

Rhodococcus equi

Corynebacterium spp

Control via environment

  • Protect wounds from contact with soil and farm animal excreta.


  • None.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Elliot G, Lawson G H & Mackenzie C P (1986) Rhodococcus equi infection in cats. Vet Rec 118 (25), 693-694 PubMed.
  • Higgins R & Paradis M (1980) Abscess caused by Corynebacterium equi in a cat. Can Vet J 21 (2), 63-64 PubMed.
  • Jang S S, Lock A, Biberstein E L et al (1975) A cat with Corynebacterium equi lymphadenitis clinically simulating lymphosarcoma. Cornell Vet 65 (2), 232-239 PubMed.