P1217 The gut microbiota as a determinant in the development of post-surgical recurrence in Crohn`s disease

Abstract

Abstract Background Crohn's disease (CD), is a chronic condition with a growing incidence in recent decades. Despite the development of new biologic therapies it is estimated that up to 70% of CD patients will require surgical intervention during their lifetime. However, surgery is not considered curative even in cases where a resection of all macroscopic involvement is performed, and the management of post-surgical recurrence remains a therapeutic challenge. Bacterial dysbiosis has been postulated as a precipitating factor in CD and may play a significant role in the development of post-surgical recurrence (PSR) of this condition. We prospectively studied the characteristics of bacterial diversity in patients with CD following ileocecal resection to identify the predictive value of intestinal microbiota in the onset of PSR. Methods We collected fecal and healthy and affected intestinal mucosal samples from 12 patients with CD who underwent surgery during the course of their disease. PSR was defined using a Rutgeerts index ≥i2b. The microbiota was assessed using 16S rRNA sequencing, and a correlation analysis was conducted between the intestinal microbiota and clinical variables of the patients. The study was conducted in accordance with the Helsinki Declaration, and all patients were recruited from among those undergoing scheduled colonoscopy for clinical indications at the Gastroenterology Unit of the University Clinical Hospital San Cecilio in Granada, Spain. Results In patients with CD and severe recurrence, mucosa-associated microbiota was characterized by a significant reduction in alpha and beta diversity compared to subjects in clinical remission. An enrichment of bacteria belonging to the phyla Bacillota and Pseudomonadota was observed, along with a reduction in Bacteroidota in subjects with PSR. We observed a negative correlation between the presence of E. coli and Shigella in patients in clinical remission and those actively undergoing treatment with biological therapy. Conclusion The recolonization of microbiota after ileocecal resection differs between patients with and without recurrence, with Fusobacteria and butyrate-producing bacteria being the most prominent contributors to driving PSR. The reduction in the abundance of short-chain fatty acid-producing bacteria and stimulators of anti-inflammatory cytokines like IL-10 could create a proinflammatory environment conducive to the development of PSR. These findings may provide valuable insights into the disease prognosis, allowing for the identification of patients at higher risk of recurrence and laying the groundwork for more targeted therapeutic approaches after surgery