1223. Impact of Helicobacter pylori Infection on Duodenal Microbial Community Structures and Microbial Metabolic Pathways

BACKGROUND: Recent reports suggest that Helicobacter pylori infection causes extragastric diseases. However, the onset mechanisms of these diseases have not been fully elucidated, and the factors involved in the onset of these extragastric diseases remain obscure. METHODS: Forty-seven (20 male, 27 female) subjects who underwent gastric cancer screening were enrolled. Aspirated duodenal fluid samples were collected from the descending duodenum. Samples were analyzed by 16S rRNA gene amplicon sequencing to investigate whether the duodenal microbiota and microbial biofunctions were affected by H. pylori infection. RESULTS: Thirteen subjects were H. pylori positive while 34 were negative. We observed 1404 bacterial operational taxonomic units from 23 phyla and 253 genera. In the H. pylori positive group, we observed higher abundance of Proteobacteria and lower abundance of Actinobacteria and TM7 than in the H. pylori negative group. The abundance of 10 genera differed significantly between the H. pylori positive and negative groups. Aspects of microbiota in the H. pylori positive group were significantly influenced by 12 taxa primarily belonging to Gammaproteobacteria, compared with those in the H. pylori negative group. Microbial functional annotation collated using the Kyoto Encyclopedia of Genes and Genomes Orthology database showed that 12 microbial metabolic pathways were significantly affected by H. pylori infection. CONCLUSION: 1. pylori infection disrupted the normal bacterial communities in the duodenum and changed aspects of the commensal microbial functions primarily by upregulating the metabolic pathways. This may be one of the principal factors in the development of extragastric diseases. DISCLOSURES: All Authors: No reported disclosures