Impact of Helicobacter Pylori Infection on Duodenal Microbial Community Structure and Microbial Metabolic Pathways

Background: The bioactivities of commensal duodenal microbiota greatly influence the biofunction of hosts. We investigated the role of Helicobacter pylori infection in extra-gastroduodenal diseases by determining the impact of H. pylori infection on the duodenal microbiota. We sequenced 16S rRNA genes in samples aspirated from the descending duodenum of 47 (male, 20; female, 27) individuals who were screened for gastric cancer. Samples were analysed using 16S rRNA gene amplicon sequencing, and the LEFSe and Kyoto Encyclopaedia of Genes and Genomes methods were used to determine whether the duodenal microflora and microbial biofunctions were affected using H. pylori infection. Results Thirteen and 34 participants tested positive and negative for H. pylori , respectively. We identified 1,404 bacterial operational taxonomic units from 23 phyla and 253 genera. H. pylori infection increased the relative mean abundance of Proteobacteria and Neisseria and decreased the abundance of the two other phyla ( Actinobacteria and TM7 ) and nine genera ( Rothia , TM7-3 , Leptotrichia , Lachnospiraceae , Megasphaera , F16 , Moryella , Filifactor , and Paludibacter ). Microbiota features were significantly influenced in H. pylori -positive participants by 12 taxa mostly classified as Gammaproteobacteria . Microbial functional annotation revealed that H. pylori significantly affected 12 microbial metabolic pathways. Conclusions H. pylori disrupted normal bacterial communities in the duodenum and changed the biofunctions of commensal microbiota primarily by upregulating specific metabolic pathways. Such upregulation may be involved in the onset of diseases associated with H. pylori infection.