PEG Laxatives for Intestinal Preparation and Gut Microbiota in Cholecystectomy

This observational study aims to investigate the impact of polyethylene glycol (PEG) laxatives used for bowel preparation on the gut microbiota of patients who have undergone cholecystectomy. Emerging evidence suggests that both cholecystectomy and high-dose PEG exposure can independently alter the intestinal microbial ecosystem. However, whether the microbiota of post-cholecystectomy patients is more vulnerable to PEG-induced perturbation and exhibits delayed recovery remains unknown. Approximately 10 adults with prior cholecystectomy scheduled for colonoscopy and 10 age-matched controls without cholecystectomy will be enrolled. All participants will undergo standard colonoscopy preparation with PEG-based laxatives. Stool samples will be collected at five time points: before bowel preparation, at the first non-watery stool after colonoscopy, and at 1, 3, and 6 months post-colonoscopy. Metagenomic shotgun sequencing will be performed to characterise the taxonomic and functional profiles of the gut microbiome. Alpha diversity, beta diversity, differential abundance, and metabolic pathway alterations will be compared within and between groups over time. The findings are expected to reveal whether cholecystectomised individuals are more susceptible to long-term gut dysbiosis after PEG exposure, and to inform future strategies for microbiota restoration in this specific population.