The presence of Sutterella spp. in mucosa and their interactions with the epithelium suggest commensalism.

Although Sutterella species have repeatedly been linked to human illnesses such as autism, down syndrome, and Inflammatory Bowel Disease (IBD), it is still unknown how these bacteria affect health. Despite the species being so common, little is known about the interactions of Sutterella spp. with the host. In this investigation, we focused on the interaction of three well-known Sutterella species with the intestinal epithelium and investigated their adhesion characteristics, impact on the function of the intestinal barrier, and in vitro pro-inflammatory capability. Additionally, we looked at the relative presence and abundance of the genus Sutterella and Sutterella wadsworthensis in intestinal biopsies from healthy people and those who had Celiac Disease (CeD) or Inflammatory Bowel Disease (IBD). Our findings demonstrate a gradient of decreasing Sutterella spp. abundance in the duodenum of healthy people. Between the paediatric IBD or CeD patients and the healthy controls, there was no discernible change in the prevalence of Sutterella. Sutterella wadsworthensis, which preferentially bound to mucus and human extracellular matrix proteins, was able to decrease the adherence of Sutterella parvirubra, which adhered to differentiated CaCO2 cells better than the other two Sutterella spp. The fact that only S. wadsworthensis caused interleukin-8 production in enterocytes suggests that the lipopolysaccharide architectures of the various species differ. However, in comparison to non-pathogenic Escherichia coli, its pro-inflammatory activity was relatively low. The integrity of the enterocyte monolayer in vitro was unaffected by Sutterella spp. According to our research, Sutterella species are common commensals with a minor pro-inflammatory potential in the human gastrointestinal tract and do not significantly contribute to the disruption of epithelial homeostasis brought on by microbiota dysbiosis and an increase in Proteobacteria. Sutterella species' capacity to cling to intestinal epithelial cells suggests that they may play an immunomodulatory role.