Temporal increase in the gastric colonization of Helicobacter pylori after healing of acetic acid-induced gastric ulcer in a miniature pig.

While the eradication of Helicobacter pylori has been reported to reduce the frequency of ulcer relapse, the preventative mechanism remains unknown. We investigated the changes in the level of gastric colonization 140 days after inducing gastric ulcer by acetic acid in the antral mucosa of a miniature pig infected with H. pylori. The gastric ulcer was induced endoscopically with 1 mL of 40% acetic acid 12 days after inoculation of H. pylori in a 3-month-old miniature pig. Gastric ulcer was healed by 30 days after ulcer induction and the levels of H. pylori in cardiac and antral mucosa increased gradually from 30 to 71 days. The peak bacterial counts in the cardia and antrum were 6.1 and 6.6 log10 cfu/g, respectively, or about 100-fold higher than the initial levels. The levels of H. pylori in cardiac and antral mucosa steadily decreased until reaching the initial levels at 127 days, while that in the fundic mucosa remained constant throughout the observation period. No ulcer recurrence was detected by endoscopy. These results suggested that the levels of H. pylori colonization increased temporally after healing of the acetic acid-induced gastric ulcer in the miniature pig.