Nocardia spp

From Dog
Gram-positive, filamentous organisms with tendency to fragmentation in coccobacillary forms of Nocardia otitidiscaviarum obtained by biopsy of cutaneous lesion in a dog.[1]
Fluctuant mass containing purulent secretion in a dog with cutaneous lesion, caused by Nocardia otitidiscaviarum[1]

Nocardia spp are a Gram-positive aerobic bacteria found commonly in soil and decaying vegetation. They enter the body through contamination of wounds or by inhalation.

Nocardia spp is an opportunistic acid-fast actinomycete that may cause disseminated disease, particularly in immunocompromised dogs[2].

Male, large-breed dogs kept outdoors were overrepresented[3].

Species pathogenic to dogs include:

  • Nocardia asteroides
  • Nocardia farcinica
  • Nocardia cyriacigeorgica
  • Nocardia abscessus
  • Nocardia otitidiscaviarum

In dogs, a number of presentations are observed: systemic, central nervous system, extrapulmonary, cutaneous and actinomycetoma. The pulmonary form involves only the lungs, the systemic form involves two or more body sites and the extrapulmonary is any primary focus without involvement of the lung and central nervous system. Actinomycetoma is a distinct subcutaneous nodule[4].

Clinically affected dogs with cutaneous forms present with subcutaneous lesions, mycetomas, and lymphadenitis. Nocardial stomatitis manifests as gingivitis and ulceration of the oral cavity, with severe halitosis.

In the disseminated form, pyothorax and osteomyelitis[5] are commonly observed, but systemic nocardiosis has also been recorded in immunosuppressed dogs such as those receiving long-term administration of cyclosporin[6][7] or in dogs co-infected with distemper virus[8].

Disseminated infections in dogs usually present clinically as lethargy, anorexia, fever, and multiple firm subcutaneous masses. Abscesses may be located within the chest[9] or brain[10].

Diagnosis is based on bacterial culture or PCR identification and speciation[11]

Nocardia spp appear to be resistant to many fluoroquinolones[12], and aggressive drainage of chest fluids and use of amoxycillin/clavulanate, amikacin, gentamicin, ceftiofur or trimethoprim-sulfamethoxazole often provide a good response to therapy.

Although systemic nocardial infections traditionally have had a grave prognosis, through early diagnosis, surgical intervention, and the use of newer, safer and synergistically acting antimicrobials, the prognosis has improved[13].

References

  1. 1.0 1.1 Ribeiro, MG et al (2008) Nocardiosis: an overview and additional report of 28 cases in cattle and dogs. Rev Inst Med trop S Paulo 50(3):177-185
  2. Paul AE et al (2010) Presumptive Nocardia spp. infection in a dog treated with cyclosporin and ketoconazole. N Z Vet J 58(5):265-268
  3. Kirpensteijn J & Fingland RB (1992) Cutaneous actinomycosis and nocardiosis in dogs: 48 cases (1980-1990). J Am Vet Med Assoc 201(6):917-920
  4. Beaman BL et al (1983) Nocardia in naturally acquired and experimental infection in animals. J Hyg 91:393–419
  5. Bradney IW (1985) Vertebral osteomyelitis due to Nocardia in a dog. Aust Vet J 62(9):315-316
  6. Smith PM et al (2007) Brain abscess in a dog immunosuppressed using cyclosporin. Vet J 173(3):675-678
  7. MacNeill AL et al (2010) Disseminated nocardiosis caused by Nocardia abscessus in a dog. Vet Clin Pathol 39(3):381-385
  8. Ribeiro MG et al (2008) Nocardiosis: an overview and additional report of 28 cases in cattle and dogs. Rev Inst Med Trop Sao Paulo 50(3):177-185
  9. Lobetti RG et al(1993) Acute fibrinopurulent pneumonia and haemoptysis associated with Nocardia asteroides in three dogs. Vet Rec 133(19):480
  10. Radaelli ST & Platt SR (2002) Bacterial meningoencephalomyelitis in dogs: a retrospective study of 23 cases (1990-1999). J Vet Intern Med 16(2):159-163
  11. Tasker S (2010) The polymerase chain reaction in the diagnosis of infectious diseases. Vet Clin Pathol 39(3):261-262
  12. Govendir M et al (2011) Susceptibility of rapidly growing mycobacteria and Nocardia isolates from cats and dogs to pradofloxacin. Vet Microbiol 153(3-4):240-245
  13. Marino DJ & Jaggy A (1993) Nocardiosis. A literature review with selected case reports in two dogs. J Vet Intern Med 7(1):4-11