Intragastric distribution of Helicobacter pylori during short-term omeprazole therapy: study using Carnoy's fixation and immunohistochemistry for detection of bacteria

Background: There is controversy about the effect of acid-suppressive thera py on Helicobacter pylori density and the severity of histological gastriti s in the corpus. Aim: To evaluate the precise distribution of H. pylori, both on the surface mucus cells and in the surface mucus gel layer, by using Carnoy's fixation and immunostaining for the detection of bacteria. Methods: A total of 19 peptic ulcer patients with H. pylori infection were studied. All patients received a 6-week course of treatment with omeprazole (20 mg/day). Before and after the therapy, H. pylori density in Carnoy-fix ed tissue sections was examined immunohistochemically. The effect of omepra zole therapy on the severity of gastritis was also evaluated. Results: H. pylori density and the grade of gastritis significantly decreas ed in the antrum after omeprazole therapy. In the corpus, however, there we re no significant changes in H. pylori density or the severity of gastritis after omeprazole therapy. Conclusion: Carnoy's fixation and immunostaining was found to be useful for the detection of H. pylori in the surface mucus gel layer as welt as on th e surface mucus cells in biopsy tissue sections. By using this method, H. p ylori density decreased in the antrum, but remained unchanged in the corpus after a 6-week course of omeprazole therapy.