Ultrastructure of another spiral organism associated with human gastritis.

Campylobacter pylori may not be the only organism that causes active chronic gastritis in man. We report two cases of gastric infection with a spiral organism distinct from C. pylori. The first patient is a 36-year-old female who presented with epigastric pain and abdominal colic present since childhood and who had 14 cats. Endoscopy was normal. The second patient kept two dogs. Histology of gastric mucosal biopsy specimens in both patients revealed active chronic gastritis, most severe in body mucosa. Giemsa stain revealed bacteria with four to eight spirals, 0.5 micron in diameter and 3-7 micron in length. The organisms had multiple sheathed flagella at the pole and smooth cell walls without axial filaments. The organisms resembled the gastric spirillum that has been seen in cats, dogs, and nonhuman primates. After antibacterial therapy with bismuth subsalicylate, amoxicillin, and metronidazole, the organisms disappeared in both patients and the gastritis healed. Unlike C. pylori, this new spirillum prefers to colonize gastric mucosa containing parietal cells. Whereas this type of organism is a common commensal in other mammals, it appears to be associated with and a possible cause of gastritis in humans.