P1214 The crosstalk between oral and intestinal microbiota in inflammatory bowel disease patients

Abstract Background Background: Previous studies reported that oral microbes can migrate to the gut, but the relationship between oral and intestinal microbiota in inflammatory bowel disease (IBD) is still unclear. Methods Here, we investigated the oral and gut microbiota of patients with Crohn’s disease (CD) and ulcerative colitis (UC), as well as their healthy relatives. We combined second- and third-generation sequencing based on the 16S rRNA gene to analyze the oral and fecal microbiota. Results A total of 97 IBD patients (59 CD and 38 UC) and 94 healthy relatives were included in the study. Our finding showed that CD and UC patients had higher levels of pathogenic bacteria in both their oral and fecal microbiota. In IBD patients, the gut microbiome was more influenced by the oral microbiome compared to healthy relatives, particularly in CD. We also observed an interesting interaction between Veillonella and Escherichia-Shigella in CD, and the presence of Veillonella in the gut was associated with disease activity. We developed diagnostic models that combined oral and fecal genera, which effectively distinguished CD (AUC=0.8478) and UC (AUC=0.7826) from healthy relatives, as well as predicted active inflammation in CD (AUC=0.9226) and UC (AUC=0.9158). Additionally, our third-generation sequencing results revealed an increase in Parvimonas micra in the oral cavity of IBD patients, and this was positively correlated with its presence in the feces. Conclusion These findings suggest that both oral and gut microbiota may play a crucial role in the development of IBD and could be potential targets for intervention.