Surgical Intervention Correlates with Reduced Bacterial Diversity in the Gut Microbiome of Crohn's Disease Patients Exhibiting Low Levels of Inflammation

Abstract

Crohn’s Disease is a type of inflammatory bowel disease characterized by dysbiosis and chronic inflammation of the gastrointestinal tract. First line therapies utilize anti-inflammatory treatments alongside endoscopies to manage and monitor disease course. Biomarkers such as fecal calprotectin are being investigated to measure inflammation and predict disease recurrence, and offer a less invasive method to track disease progression. Surgical resection serves as a last resort treatment to medical therapies, but this alternative has been shown to alter microbial diversity post-operatively. This study aims to identify the link between inflammation and microbial composition in Crohn’s Disease patients with or without surgical resection. Diversity analysis revealed reduced alpha diversity in Crohn's Disease patients following surgical intervention. This observation was minimal in patients with pre-existing inflammation compared to those without inflammation. In parallel, we ran the same diversity analysis based on disease severity. We found that inflammation masked the reduction in alpha diversity in patients with more severe disease, consistent with the effects of inflammation on surgical resection. Additionally, indicator species analysis revealed reduced abundance of anti-inflammatory taxa in patients following surgical resection. These findings provide insight into the post-operative intestinal environment, and can help inform post-operative care and limit significant alterations to the gut microbiome in an already dysbiotic environment.