Canis ISSN: 2398-2942

Nocardia spp

Contributor(s): Richard Walker

Introduction

Classification

Taxonomy

  • Order: Actinomycetales.
  • Family: Nocardiaceae.
  • Genus: Nocardia.

Etymology

  • Named after Edmond Nocard, a French veterinarian.

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Clinical Effects

Epidemiology

Habitat

  • Thrive in the environment.
  • Saprophytes found in many climates in soil and water.
  • May exist as indigenous flora or contaminants.

Lifecycle

  • Actively growing filaments alternate with resting coccobacillary form.

Transmission

  • Inhalation - pulmonary disease.
  • Soil contamination of wounds.

Pathological effects

  • Antibody-mediated and cell-mediated immune responses, including allergy, often develop during nocardial infections.
  • Severe infection may occur in immunosuppressed animals, particularly of cell-mediated immunity.
  • Disease does not usually occur unless there are a large number of organisms and some immunosuppression in the host to which it is exposed.
  • Prevent phagolysosome production and therefore survive within phagocytic vacuoles of the host cells. Due to cell wall lipids, similar to Mycobacterium spp.
  • Characteristic granulomas result.
  • Exudates may contain soft granules of bacteria and neutrophils but NOT the sulfur granules typical of Actinomyces spp.
  • Nocardia asteroides is responsible for various granulomatous infections and abscess formation in a wide range of animals, most commonly localized granulomatous abscesses and pyothorax in the thoracic cavity in dogs and cats, and chronic granulomatous mastitis in cattle.
  • Nocardia farcinata causes farcy in cattle in tropical countries.
  • Nocardia brasiliensis and Nocardia otiditis-caviarum mainly cause infections in man.

Other Host Effects

  • Essentially saprophytic.

Control

Control via chemotherapies

  • Limited range of effective antimicrobial agents.
  • Trimethoprim-sulfamethoxazole Trimethoprim is the most effective.
  • Macrolides and tetracyclines are also effective.

Other countermeasures

  • Drainage of pus.
  • Surgical excision where feasible.

Diagnosis

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Further Reading

Publications

Refereed papers

  • Recent references from VetMedResource and PubMed.
  • Lobetti R G, Collett M G & Leisewitz A (1993) Acute fibrinopurulent pneumonia and haemoptysis associated with Nocardia asteroides in three dogs. Vet Rec 133(19), 480.
  • Marino D J & Jaggy A (1993) Nocardiosis. A literature review with selected case reports in two dogs. J Vet Intern Med 7(1), 4-11.
  • Kirpensteijn J & Fingland R B (1992) Cutaneous actinomycosis and nocardiosis in dogs - 48 cases (1980-1990). JAVMA 201(6), 917-20.

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