Open Collections

Abstract

Bowel preparation (prep) is a common practice that precedes colonoscopy procedures in the clinic to clear out luminal contents of the gastrointestinal tract (GIT). Most commonly, osmotic-based laxatives are used for bowel prep based on ease of administration and are considered harmless to patients. One of the most common osmotic laxatives used in the clinic is polyethylene glycol (PEG), which functions by increasing osmolyte concentration in the gut lumen and promoting gut motility. The human gut microbiota, a diverse group of microorganisms in the GIT, plays a crucial role in health. Recent studies indicate that osmotic stress alters the gut environment, selecting for osmotically tolerant bacteria in the microbiota. This study aimed to investigate the effects of bowel prep on the gut microenvironment and microbiota. Using a murine model, we observed changes in the GIT essential for colonization resistance. To determine if bowel prep impairs this resistance, we examined pathogen infection and expansion in the gut microbiota. We tested Salmonella enterica, an organism known for its osmotic resistance and role in host-pathogen interactions. Our findings showed that bowel prep disrupts the gut's physical environment, reducing colonization resistance and significantly increasing Salmonella colonization and translocation to extra-intestinal organs. GIT tissue imaging showed changes to the mucus layer and epithelial damage due to Salmonella post-bowel prep. Building on these findings, we explored how bowel prep affects microbiota with existing pathogenic bacteria, focusing on inflammatory bowel disease (IBD), a chronic GIT disorder. Although the cause of IBD is unknown, research highlights the prevalence of pathobionts, bacteria that become pathogenic under certain conditions. Some IBD patients experience inflammatory episodes post-bowel prep, leading to emergency room visits and reluctance to undergo colonoscopies. We transplanted an IBD patient’s microbiota into a mouse model and found that post-bowel prep, IBD pathobiont bacterial translocation persisted for two weeks. These findings offer insights into pathogen infection mechanisms following bowel prep and reveal how osmotic perturbations can exacerbate pathogen and pathobiont activity in the gut. This research investigates potential mechanisms behind pathogen infection post-gut disruption and highlights the systemic effects of bowel prep on the host.