Duodenal microbiome profiles exhibit sex-specific differences.

Prior research using stool samples has shown that gut microbiome composition differs between males and females. As the small bowel microbiome plays key roles in host metabolic and immune health, we compared the duodenal lumenal microbiome in male and female subjects. The core duodenal microbiome differed significantly between sexes: genus Granulicatella was more prevalent in females, whereas Leptotrichia formed part of the core in males only. Microbial network analysis revealed differences in the number, composition, and interconnectivity of duodenal microbial communities in females vs. males, with tighter network interconnectivity in males, and higher network eccentricity in females that may reflect greater susceptibility to environmental fluctuations. A unique microbial community in females including Streptococcus, Granulicatella, Escherichia/Shigella, and Rothia was associated with differences in several predicted microbial metabolic pathways, including decreased bile acid deconjugation and fructan biosynthesis in females. Understanding these differences may help elucidate sex-specific differences in human health and disease.