Helicobacter Infection

The majority of Helicobacter infections colonize in mammalian stomachs and intestines. Three are considered human pathogens. The most significant is H. pylori which causes gastritis and peptic ulcer; the latter may progress to gastric carcinoma. A number of Helicobacer species have been isolated from the stomachs of dogs and cats including H. felis and H. heilmannii; H. pylori occurs in the stomach of the cat. They occur in the gastric mucus layer and their capacity to breakdown urea with the production of ammonia and carbon dioxide with the consequent raising of the pH contributes to their survival. There has been much debate about the pathogenic significance of these organisms in dogs and cats. Evidence suggests that they can cause a mild gastritis in both species.

Clinical Signs -

The following signs have been attributed to Helicobacter infections in dogs and cats: vomiting, regurgitation, abdominal pain, fever, diarrhea, anorexia, weight loss and poor condition.

Diagnosis -

Isolation and identification or demonstration of characteristic helical organisms along with evidence of gastritis warrants a diagnosis. Evidence of urease is supportive. Scrapings of the gastric mucosa are examined under darkfield microscopy for helical shaped organisms. These organisms can also be seen in stained sections of gastric biopsies. Biopsy material taken endoscopically from areas of gastritis: Attempts are made to isolate and identify Helicobacter organisms; however, H. heilmannii, the most common species in dogs and cats, has not been cultured on artificial media. Helicobacter felis is difficult to isolate and identify.

Treatment -

Metronidazole with amoxicillin, or metronidazole (cat: 10 - 20 mg/kg, PO, 12 - 24 hour interval; dog: 15 - 30 mg/kg, 12 - 24 hour interval) with tetracycline and both combinations with bismuth subsalicylate (Pepto-Bismol):1 - 3 ml/kg/day, in divided doses for 2 - 3 weeks have been effective. Amoxicillin with omeprazole (inhibits gastric acid secretion), 20 mg for each dog. Cimetidine (10 mg/kg, 6 - 8 hour interval) is also used to reduce gastric acid. Specific treatment regimens for dogs and cats are not yet available. The drugs mentioned above will greatly reduce the number of gastric bacteria in dogs and cats but recurrence of infection appears to be common.