infection alters gastric microbiota structure and biological functions in patients with gastric ulcer or duodenal ulcer.

Background: infection is closely associated with gastrointestinal diseases. Our preliminary studies have indicated that infection had a significant impact on the mucosal microbiome structure in patients with gastric ulcer (GU) or duodenal ulcer (DU).

Aim: To investigate the contributions of . infection and the mucosal microbiome to the pathogenesis and progression of ulcerative diseases.

Methods: Patients with . infection and either GU or DU, and healthy individuals without . infection were included. Gastric or duodenal mucosal samples was obtained and subjected to metagenomic sequencing. The compositions of the microbial communities and their metabolic functions in the mucosal tissues were analyzed.

Results: Compared with that in the healthy individuals, the gastric mucosal microbiota in the . -positive patients with GU was dominated by . , with significantly reduced biodiversity. The intergroup differential functions, which were enriched in the . -positive GU patients, were all derived from . , particularly those concerning transfer RNA queuosine-modification and the synthesis of demethylmenaquinones or menaquinones. A significant enrichment of the gene was detected in the synthesis pathway. There was no significant difference in microbial diversity between the -positive DU patients and healthy controls.

Conclusion: . infection significantly alters the gastric microbiota structure, diversity, and biological functions, which may be important contributing factors for GU.