Helicobacter spp

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Helicobacter spp are a ubiquitous zoonotic Gram-negative, microaerophilic bacteria of the dog oropharynx, stomach and colon are regularly found amongst the fecal biotome.

Species of Helicobacteraceae which are pathogenic to dogs include:

  • Helicobacter pylori[1] - gastritis
  • Helicobacter heilmannii - stomach and colon[2]
  • Helicobacter felis - stomach and colon[3]
  • Helicobacter acinonychis[4]
  • Helicobacter bizzozeronii[5]
  • Helicobacter bilis/flexispira[6][7]
  • Helicobacter cinaedi
  • Helicobacter canis
  • Flexispira rappini[8]
  • Helicobacter marmotae - prairie dogs
  • Wolinella spp[9] - oral cavity

These bacteria inhabit the stomach and to a lesser degree, the intestine and liver. They break down urea into ammonia and bicarbonate and thus create a less acidic microenvironment in order to survive. The overall prevalence rates of Helicobacter are high in both dogs (80-100%) and humans (20-100%). Most Helicobacter infections are not associated with clinical signs. Nevertheless, these bacteria have the potential to cause disease.

Helicobacter are enterohepatic, able to colonize the large intestine and liver of healthy and symptomatic dogs[10].

The helicobacteraceae group normally reside intracellularly within parietal cells of the gastric fundus[11] and small and large intestines and are predominantly associated with gastritis, ulcerative colitis and biliary/hepatic disease[12].

Coinfections with other organisms such as Campylobacter spp and Arcobacter spp is common[13].

Infections are usually acquired at a young age in dogs, presumably from the bitch.

Diagnosis is based on presenting clinical signs of vomiting and/or diarrhea[14], augmented with isolation and specific culture or PCR assays for determining presence of Helicobacter spp in gastric swabs.

Treatment usually involves a 7 - 14 day course of triple antimicrobial therapy such as combinations of clarithromycin, amoxicillin and omeprazole or lansoprazole[15].

Although medical therapy is useful in resolution of clinical signs and clearance of visible Helicobacter spp, gastric inflammation commonly persist for some time afterwards, necessitating longer term proton-pump inhibitor therapy[16].

References

  1. Polanco R et al (2011) High prevalence of DNA from non-H. pylori helicobacters in the gastric mucosa of Venezuelan pet dogs and its histological alterations. Rev Inst Med Trop Sao Paulo 53(4):207-212
  2. Duquenoy A & Le Luyer B (2009) Gastritis caused by Helicobacter heilmannii probably transmitted from dog to child. Arch Pediatr 16(5):426-429
  3. Arnold IC et al (2011) Comparative whole genome sequence analysis of the carcinogenic bacterial model pathogen Helicobacter felis. Genome Biol Evol 3:302-308
  4. Asl AS et al(2010) Detection of atypical cultivable canine gastric Helicobacter strain and its biochemical and morphological characters in naturally infected dogs. Zoonoses Public Health 57(4):244-248
  5. Recordati C et al (2009) Spatial distribution of Helicobacter spp. in the gastrointestinal tract of dogs. Helicobacter 14(3):180-191
  6. Hänninen ML et al (2005) Extension of the species Helicobacter bilis to include the reference strains of Helicobacter sp. flexispira taxa 2, 3 and 8 and Finnish canine and feline flexispira strains. Int J Syst Evol Microbiol 55(2):891-898
  7. Kostia S et al (2003) Cytolethal distending toxin B gene (cdtB) homologues in taxa 2, 3 and 8 and in six canine isolates of Helicobacter sp. flexispira. J Med Microbiol 52(2):103-108
  8. Kipar A et al (2001) Fatal gastrointestinal infection with 'Flexispira rappini'-like organisms in a cat. J Vet Med B Infect Dis Vet Public Health 48(5):357-365
  9. Craven M et al (2011) Evaluation of the Helicobacteraceae in the oral cavity of dogs. Am J Vet Res 72(11):1476-1481
  10. Castiglioni V et al(2012) Enterohepatic Helicobacter spp. in colonic biopsies of dogs: molecular, histopathological and immunohistochemical investigations. Vet Microbiol 159(1-2):107-114
  11. Lanzoni A et al (2011) Localization of Helicobacter spp. in the fundic mucosa of laboratory Beagle dogs: an ultrastructural study. Vet Res 42(1):42
  12. Smet A et al (2011) The other Helicobacters. Helicobacter 16(1):70-75
  13. Houf K et al (2008) Dogs as carriers of the emerging pathogen Arcobacter. Vet Microbiol 130(1-2):208-213
  14. Ellis AE et al (2010) Diagnostic exercise: chronic vomiting in a dog. Vet Pathol 47(5):991-993
  15. Anacleto TP et al (2011) Studies of distribution and recurrence of Helicobacter spp. gastric mucosa of dogs after triple therapy. Acta Cir Bras 26(2):82-87
  16. Jergens AE et al (2009) Fluorescence in situ hybridization confirms clearance of visible Helicobacter spp. associated with gastritis in dogs and cats. J Vet Intern Med 23(1):16-23