Bismuth salts with versus without acid suppression for Helicobacter pylori infection: A transmission electron microscope study

BACKGROUND: Bismuth oxychloride produced by interaction of bismuth compounds with gastric acid is believed to damage Helicobacter pylori. The effect of bismuth salts on H. pylori in the presence of strong acid suppression is unknown. This randomized trial aimed to determine effects of bismuth subcitrate on H. pylori with and without acid suppression. METHODS: H. pylori -positive participants were allocated (1:1:1) to receive (a) no treatment (control), (b) colloidal bismuth subcitrate (CBS, 125 mg/tab), or (c) CBS plus high-dose proton-pump inhibitor (PPI), esomeprazole 40 mg q.i.d. for 3 days. In the treatment groups, CBS was given: 1 dose, 1 hour before endoscopy, 1 dose, 4 hours before endoscopy, or q.i.d. 24 hours before endoscopy. The study end-points were evaluated using transmission electron microscopy to observe the morphological changes of H. pylori in antral and corpus biopsies. RESULTS: Twenty-seven H. pylori carriers were enrolled in this trial with qualitative end-points. In the no treatment group, active budding and replication of H. pylori were observed. In the CBS group, cellular swelling, vacuolization, structural degradation, and cell wall eruption of H. pylori were observed, with no apparent association with when the CBS was given. Among those receiving high-dose PPI-plus CBS or CBS only, there were no differences in number of H. pylori present or severity of bacterial damage whether CBS was given 1, 4, or 24 hours before endoscopy. CONCLUSIONS: Based on direct morphological evaluation, the toxic effect of CBS treatment on H. pylori was demonstrated independent of acid suppression with PPI.