Capnocytophaga spp

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Gross image of accessory lung lobe, associated with plant awn aspiration and secondary infection with Capnocytophaga spp. Note the exudate in all of the airways[1]

Capnocytophaga spp are a commensal Gram-negative zoonotic capnophilic bacteria found in the periodontal space of the dog.

These bacteria are found more commonly in male dogs of small breeds ('post-man bites'), and diets rich in carbohydrates may predispose to higher colonization rates[2][3].

These bacteria, although rarely associated with canine gingivitis[4], can cause sepsis, deafness and meningitis in humans[5].

Capnocytophaga spp have both passive and active mechanisms of immune evasion to escape from the dog's host immune system[6].

Species which have been reported in dogs include:

  • Capnocytophaga canimorsus[7]
  • Capnocytophaga ochracea
  • Capnocytophaga sputigena[8]
  • Capnocytophaga cynodegmi[9]
  • Capnocytophaga haemolytica

Male dogs of small breeds have a higher predilection to carrying C. canimorsus.

  • Capnocytophaga gingivalis
  • Capnocytophaga granulosa[10]

The bacterium has been isolated from humans, infected by dog bites, scratches, licks or simply exposure to dogs[11]. In humans, C. cynodegmi typically causes localized cellulitis of various severities[12]. Other local infections such as keratitis can occur. Systemic infections such as meningoencephalitis and generalized sepsis have been reported in splenectomized patients, as well as those with predisposing conditions such as diabetes, alcoholism, and cirrhosis.

In dogs, rare cases of secondary infections with Capnocytophaga spp have been reported following oral trauma or foreign body aspiration.

Diagnosis can be confirmed on culture but PCR assays are usually definitive in establishing a diagnosis[13].

This bacteria is reportedly sensitive to enrofloxacin[14][15].


  1. Workman HC et al (2008) Capnocytophaga cynodegmi in a rottweiler dog with severe bronchitis and foreign-body pneumonia. J Clin Microbiol 46(12):4099-4103
  2. Logan EI et al (2006) Dietary influences on periodontal health in dogs and cats. Vet Clin North Am Small Anim Pract 36(6):1385-1401
  3. Signoretto C et al (2012) Functional foods and strategies contrasting bacterial adhesion. Curr Opin Biotechnol 23(2):160-167
  4. Mally M et al (2009) Prevalence of Capnocytophaga canimorsus in dogs and occurrence of potential virulence factors. Microbes Infect 11(4):509-514
  5. Gasch O e al (2009) Community-acquired Capnocytophaga canimorsus meningitis in adults: report of one case with a subacute course and deafness, and literature review. Enferm Infecc Microbiol Clin 27(1):33-36
  6. Shin H et al (2007) Escape from immune surveillance by Capnocytophaga canimorsus. J Infect Dis 195(3):375-386
  7. Teo KG et al (2012) Asplenic fulminant sepsis secondary to a dog bite complicated by toxic epidermal necrolysis/Stevens-Johnson syndrome. N Z Med J 125(1358):74-77
  8. Kato Y et al (2011) Molecular detection of human periodontal pathogens in oral swab specimens from dogs in Japan. J Vet Dent 28(2):84-89
  9. Lipman L et al (2011) The presence of Capnocytophaga canimorsus and Capnocytophaga cynodegmi in companion animals in the Netherlands. Tijdschr Diergeneeskd 136(7):490-492
  10. Dilegge SK et al (2011) Presence of the oral bacterium Capnocytophaga canimorsus in the tooth plaque of canines. Vet Microbiol 149(3-4):437-445
  11. Gaastra W & Lipman LJ (2010) Capnocytophaga canimorsus. Vet Microbiol 140(3-4):339-346
  12. Greene, CE (1998) Infectious diseases of the dog and cat, 2nd ed. pp:582-594. W. B. Saunders Company, St. Louis, MO
  13. Suzuki M et al (2010) Prevalence of Capnocytophaga canimorsus and Capnocytophaga cynodegmi in dogs and cats determined by using a newly established species-specific PCR. Vet Microbiol 144(1-2):172-176
  14. Forman, MA et al (2005) Lower respiratory tract infection due to Capnocytophaga cynodegmi in a cat with pulmonary carcinoma. J Feline Med Surg pp:7227-231
  15. Le Moal, G et al (2003) Meningitis due to Capnocytophaga canimorsus after receipt of a dog bite: case report and review of the literature. Clin Infect Dis 36:42-46