The Effect of Quadruple Therapy with Polaprezinc or Bismuth on Gut Microbiota after Helicobacter pylori Eradication: A Randomized Controlled Trial

Background: Quadruple therapy with polaprezinc provided an alternative to Helicobacter pylori eradication; however, the effect on gut microbiota remains uncertain. This study aims to identify whether polaprezinc-containing quadruple therapy causes adverse microbiota effects among asymptomatic adults, compared with bismuth therapy. Methods: This was a randomized control trial. One hundred asymptomatic H. pylori-infected adults were randomly (1:1) assigned to two treatment groups (polaprezinc-containing therapy, PQT; or bismuth-containing therapy, BQT). Fecal samples were collected from subjects before and 4–8 weeks after therapy. Samples were sequenced for the V4 regions of the 16S rRNA gene. Results: The relative abundance of the three dominant bacterial phyla (Bacteroidota, Firmicutes, and Proteobacteria) accounted for more than 95% of each treatment group. The alpha diversity between eradications that succeeded and those that failed had no significant difference (p > 0.05). After successful eradication, the alpha diversity in the BQT group decreased in comparison with the baseline (p < 0.05). Subjects who were successfully eradicated by BQT showed considerably lower alpha diversity indices than those of the PQT at follow-up (p < 0.05). The abundance of Parasutterella in subjects who were successfully eradicated by PQT was four times greater than that of BQT (q < 0.05). Conclusion: A 14-day PQT may be superior to BQT in maintaining short-term gut microbiota homeostasis after H. pylori treatment. Our findings preliminarily provide evidence of the short-term impacts of the gut microbiota after PQT treatment of H. pylori infection.