Effect of gut microbiota on the recovery of bowel function for patients undergoing colon surgery: a prospective cohort study

Purpose This study explored risk factors and gut microbiome characteristics associated with postoperative bowel functional recovery in patients undergoing colorectal surgery. Methods Patients undergoing colorectal surgery between January 2023 and October 2023 were stratified into two cohorts based on the timing of their first postoperative defecation (≤ 5 days vs. >5 days). Clinical data were systematically recorded to identify independent risk factors for delayed bowel recovery. Fresh postoperative stool specimens were collected and analyzed using metagenomic sequencing to examine the relationship between gut microbiota composition and bowel functional outcomes. Results Thirty-five patients were enrolled. Multivariate analysis identified the timing of first postoperative enteral feeding ( p  < 0.01) as an independent risk factor for delayed defecation. Alpha diversity indices showed no significant differences between groups in microbial species richness. However, patients with delayed defecation (> 5 days) exhibited a lower relative abundance of probiotic taxa (e.g., Bifidobacterium, Lactobacillus) and an increased abundance of pathogenic bacteria compared to the ≤ 5-day cohort. Metagenomic profiling further demonstrated impaired microbial metabolic pathways in the delayed recovery group, including reduced carbohydrate metabolism (e.g., glycolysis/gluconeogenesis) and amino acid metabolism (e.g., selenocysteine and taurine biosynthesis). Conclusions Early postoperative resumption of enteral nutrition and probiotics may enhance bowel functional recovery. The observed reductions in microbial-driven gluconeogenesis/glycolysis, selenocysteine, and taurine synthesis suggest dysregulation of these metabolic pathways may compromise intestinal mucosal repair and homeostasis, contributing to delayed postoperative recovery.