Brachyspira spp

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Brachyspira spp viewed under light microscopy[1]

Brachyspira spp (formerly Serpulina spp) are a Gram-negative, anaerobic spirochaete which normally resides in the large intestinal microbiota of most dogs worldwide and is considered an emerging cause of mild pathogenic diarrhea in dogs in low socioeconomic regions[2].

In the colon this spirochaete can penetrate the overlying mucus layer, attach by one cell end to the underlying enterocytes, and initiate localized colitis and diarrhoea[3].

Prevalence rates in dogs are about 5% of the canine population and the organisms are transmitted between dogs by the fecal-oral route[4].

Species which have been identified in dogs include:

  • Brachyspira pilosicoli (zoonotic)[5]
  • Brachyspira canis
  • Brachyspira intermedia
  • Brachyspira alvinipulli[6]

A significant rise in the presence of Brachyspira equates directly to the occurrence of diarrhea, but their role in the etiopathogenisis of diarrhea in clinically settings is unknown[7], although they have been isolated in 10% of dogs with diarrhea[8].

Common symptoms in dogs are intermittent, chronic diarrhea that is sometimes mucohemorrhagic[9].

Diagnosis is based on selective anaerobic culture of the organism and PCR assays speciation. Pathological examination of intestinal biopsies usually reveals macro- and microscopical lesions of colitis with the bacteria in the lumens of the crypts, in goblet cells and within the colonic epithelium[10].

A differential diagnosis would consider other more common causes of canine diarrhea such as endoparasites, canine adenovirus, Campylobacter jejuni, Giardia spp and Helicobacter spp.

Treatment is effective with gentamicin, clindamycin and trimethoprim-sulfamethoxazole[11].


  2. Duhamel GE (2001) Comparative pathology and pathogenesis of naturally acquired and experimentally induced colonic spirochetosis. Anim Health Res Rev 2(1):3-17
  3. Naresh R & Hampson DJ (2010) Attraction of Brachyspira pilosicoli to mucin. Microbiology 156(1):191-197
  4. Smith JL (2005) Colonic spirochetosis in animals and humans. J Food Prot 68(7):1525-1534
  5. Oxberry SL & Hampson DJ (2003) Colonisation of pet shop puppies with Brachyspira pilosicoli. Vet Microbiol 93(2):167-174
  6. Johansson KE et al (2004) Identification of three clusters of canine intestinal spirochaetes by biochemical and 16S rDNA sequence analysis. J Med Microbiol 53(4):345-350
  7. Hidalgo A et al (2010) Prevalence of Brachyspira pilosicoli and "Brachyspira canis" in dogs and their association with diarrhoea. Vet Microbiol 146(3-4):356-360
  8. Prapasarakul N et al (2011) Faecal excretion of intestinal spirochaetes by urban dogs, and their pathogenicity in a chick model of intestinal spirochaetosis. Res Vet Sci 91(3):e38-e43
  9. Manabe M et al(2004) Brachyspira pilosicoli isolated from two beagles and one mongrel in Japan. J Vet Med Sci 66(5):589-592
  10. Fellström C et al (2001) Classification of Brachyspira spp. isolated from Swedish dogs. Anim Health Res Rev 2(1):75-82
  11. Duhamel, DE et al (1998) In vitro activity of four antimicrobial agents against North American isolates of porcine Sepulina pisicoli. J Vet Diag Invest 10:448