Biophysical Society Thematic Meeting | Ascona 2026

Mechanobiology of Infection

Monday Speaker Abstracts

MECHANOBIOLOGICAL CONSEQUENCES OF BOWEL PREP: WEAKENED BARRIERS AND PATHOGEN TRANSLOCATION Carolina Tropini University of British Columbia, Vancouver, BC, Canada Mechanical forces and physicochemical parameters within the gut are central regulators of host– microbe interactions, yet clinical procedures that acutely perturb this environment are rarely examined through a mechanobiological lens. Bowel preparation (BP), an osmotic laxative regimen routinely administered prior to colonoscopy, induces rapid fluid shifts and mechanical clearance of luminal contents. Despite its widespread use, its impact on mucosal barrier mechanics and susceptibility to infection has remained poorly defined. Using reductionist mouse models, humanized microbiota systems, and in vitro approaches, we demonstrate that polyethylene glycol–based BP constitutes a transient but profound biomechanical disruption of the gut ecosystem. Within hours, BP increases luminal osmolality, depletes short-chain fatty acids, and decimates the mucus layer, reducing both its thickness and epithelial coverage. These changes occur without overt epithelial damage yet significantly weaken colonization resistance. Under these mechanically altered conditions, Salmonella enterica serovar Typhimurium robustly colonizes the gut in the absence of antibiotics, including non-motile mutants typically impaired in invasion. BP further facilitates pathogen translocation to mesenteric lymph nodes, liver, and spleen, and exacerbates inflammation in a chemically induced colitis model. Mechanistically, our findings suggest that osmotic stress and mucus depletion together reshape the physical landscape that constrains microbial access to the epithelium. By transiently altering barrier mechanics, nutrient availability, and spatial organization, BP lowers the threshold for pathogen establishment and systemic dissemination. These results position bowel preparation as a clinically relevant model of acute biomechanical perturbation, revealing how short-lived shifts in tissue mechanics and luminal environment can have outsized consequences for infection biology. More broadly, this work underscores the importance of integrating mechanical and biophysical parameters into our understanding of host–pathogen interactions, particularly in vulnerable populations such as individuals with inflammatory bowel disease.

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