The impact of Helicobacter pylori infection, eradication therapy, and probiotics intervention on gastric microbiota in young adults.

Background: The impact of probiotics on non-Helicobacter pylori gastric microbiota and its role in microbial restoration after eradication were relatively unknown. We aimed to explore the effect of H. pylori eradication and probiotic intervention on gastric microbiota in young adults.

Methods: Fifty-six H. pylori-negative and 95 H. pylori-positive subjects aged 19-30 were included in this study. H. pylori-infected individuals were randomly assigned to quadruple therapy, probiotics supplemented quadruple therapy, or probiotics monotherapy group. Gastric mucosa and gastric juice samples were collected before and 2 months after treatment for 16SrRNA gene sequencing.

Results: The gastric microbial community structure and composition differed from H. pylori-negative subjects 2 months after successful H. pylori eradication. The α diversity of gastric mucosal microbiota significantly increased and was higher than H. pylori-negative subjects, while the α diversity of gastric juice microbiota decreased and was lower than the H. pylori-negative. After probiotics supplemented eradication treatment, Bifidobacterium was enriched in gastric mucosa, Lactobacillus was enriched in gastric juice, potentially pathogenic bacteria such as Fusobacterium and Campylobacter decreased, and the microbial diversity was closer to that of H. pylori-negative subjects compared to quadruple therapy group. Probiotics monotherapy significantly altered the diversity, community structure, and composition of gastric microbiota but showed no advantage in H. pylori inhibition and upregulating beneficial bacteria such as Bifidobacterium and Lactobacillus and related metabolism pathways. Certain potentially pathogenic bacteria such as Fusobacterium increased after probiotic monotherapy.

Conclusion: H. pylori eradication significantly disrupted gastric microbiota in young adults and could not be restored in a short time. Probiotics supplementation partially helped restore the gastric dysbiosis caused by eradication therapy, but it might be unnecessary for H. pylori-infected young adults to take probiotics alone.