Helicobacter

Overview

Helicobacter spp. are related to Campylobacter species and Arcobacter species and are pathogens affecting the stomach.Unlike many bacterial pathogens Helicobacter spp. are able to survive in the extremely low pH environment that exists within the stomach. The genus was first discovered in the stomach of humans in 1987. There are several species identified in humans and many veterinary species where the incidence of some species of Helicobacter is high. Species such as H. felis, H. bizzozeronii, H. salomonis and H. bilis have been identified in the gastric mucosa and intestines of dogs and cats. The genus is however considered of low pathogenic significance in veterinary species but there is possibility of zoonosis of the H. pylori species that is the causitve agent of gastric disease in humans. However H.pylori has not been identified in cats and is rarely seen in cats. The major veterinary concern posed by Helicobacter spp. is the H. mustelae that has been associated with chronic gastritis and gastric ulcers in ferrets.

• Discovered in the stomach of humans in 1987

Characteristics

Helicobacter are gram negative rod bacteria, they can appear helical, S-shaped or curved.

• Helical, S-shaped or curved Gram negative rods
• Require enriched media; some grow on Skirrow agar
• Microaerophilic, non-saccharolytic
• Oxidase positive and catalase positive except for H. canis
• Helicobacters which colonise gastric mucosa are urease positive

Clinical infections

• Helicobacter pylori causes gastritis and duodenal and gastric ulcers in humans
• Association with gastric adenocarcinoma in humans
• H. mustelae has been associated with chronic gastritis and gastric ulcers in ferrets
• Significance in gastrointestinal diseases of domestic carnivores not known

• Carried in the stomach of a high proportion of people.
  • 60% in the elderly.
• Implicated in the development of peptic ulcers and gastritis in people.
• Strong epidemiological evidence for the involvement of H. pylori in human gastric neoplasia.
  • No evidence this is the case for animals.
• Several species demonstrated in dogs: H. felis, H. bizzozeronii, H. salomonis and H. bilis.
  • Present in around 80% of clinically healthy pet dogs.
    • Up to 100% in dogs from animal shelters.
• Experimental infection of dogs has failed to show a consistent relationship between infection with Helicobacter and pathology.
  • Inflammation accompanies infection in some but not all infected dogs.