Intragastric bacterial infection and endoscopic findings in Helicobacter pylori-negative patients.

In the present study, the authors examined the association between gastric bacterial infection and gastric endoscopic findings in Helicobacter pylori (H. pylori)-negative patients. The subjects were 105 H. pylori-negative patients. The mean age was 72.8 ± 9.1 years. Endoscopy and gastric juice culture were performed. The presence or absence of endoscopic findings was checked according to the Kyoto classification of gastritis. Culture was positive in 69 patients (65.7%), with Streptococcus α-hemolytic being the most common (51 patients), followed by Neisseria sp. (43 patients). According to the univariate analysis, there was a significant difference between the results of culture and background factors in the use of gastric antisecretory drugs and between the results of culture and various endoscopic findings in atrophic gastritis, intestinal metaplasia, regular arrangement of collecting venule, mucosal swelling, sticky mucus, hyperplastic polyps, hematin, and gastric cobblestone-like lesions. Furthermore, multivariate analysis revealed significant differences in background factors such as the use of gastric antisecretory drugs and endoscopic findings only in patients with mucosal swelling. Endoscopic findings of non-H. pylori bacteria-positive gastritis differed from endoscopic findings of H. pylori-infected gastritis in several respects. In conclusion, our results suggest that non-H. pylori bacteria may infect the stomach and cause gastric inflammation, especially in patients who long term use gastric antisecretory drugs.