Impact of Helicobacter Pylori Eradication Therapy on Gastric Microbiome

Abstract

\n Background: Helicobacter pylori (Hp) eradication therapy has been used in clinical practice for many years. Yet, the effect of this therapy on existing gastric microflora has not been well understood. In this study, we explored the effect of eradication therapy on the microbial community in the stomach and the specific recovery after the successful eradication therapy. Methods: Among the 89 included patients, 23, 17, 40, and 9 were enrolled into the Hp-negative, Hp-positive, Successful eradication, and Failed eradication groups, respectively. Four subgroups were further divided according to disease status (Hp-negative chronic gastritis [N-CG], Hp-negative atrophic gastritis [N-AG], successful-eradication chronic gastritis [SE-CG], and atrophic gastritis with successful eradication [SE-AG]). During the endoscopic examination, one piece of gastric mucosa tissue was obtained from the lesser curvature side of the gastric antrum and gastric corpus, respectively. 16S rRNA gene sequencing was used to analyze the gastric mucosal microbiome. Results: In Hp negative group, the gastric microbiota was dominated by five phyla: Firmicutes , Proteobacteria , Actinobacteria , Bacteroidetes, and Fusobacteria . Two Hp-related genera were selected as potential biomarkers: Curvibacter and Acinetobacter . After successfully eradicating Hp, the bacterial flora in the stomach recovered to a considerable extent, and the failure of eradication was almost unchanged compared with Hp positive subjects. SE-CG was characterized by an increase in Firmicutes taxa and a decrease in Proteobacteria taxa compared with N-CG. SE-AG was characterized by a decrease in Firmicutes relative to N-AG. Finally, no differences were found in pairwise comparisons of nitrate and nitrite reductase functions among the four subgroups. Conclusions: After Hp infection, the diversity and relative abundance of gastric microflora were significantly decreased. Yet, gastric microbiota could be partially restored to the Hp-negative status after eradication; however, this effect was incomplete and might contribute to the long-term risks.