Deprivation of dietary fiber in specific-pathogen-free mice promotes susceptibility to the intestinal mucosal pathogen Citrobacter rodentium. SPF-CITROBACTER

Background: The change of dietary habits in Western societies, including reduced consumption of fiber, is linked to alterations in the gut microbial ecology. Nevertheless, little is known about how these changes in the gut microbiota composition and function affect colonization resistance and susceptibility to infections by enteric pathogens. Results: We sought to investigate how a diet devoid of plant fibers impacts the structure and function of a homeostatic gut microbiota in specific-pathogen-free (SPF) mice and how such changes alter susceptibility to a rodent enteric pathogen. We show that absence of dietary fiber intake leads to shifts in the abundances of specific taxa, erosion of the colonic mucus barrier, a reduction of intestinal barrier-promoting short-chain fatty acids, and increases in markers of mucosal barrier integrity disruption. Importantly, our results highlight that these fiber-deprived diet-led changes in the gut microbial ecology collectively contribute to a lethal colitis by the mucosal pathogen Citrobacter rodentium, which is used as a mouse model for enteropathogenic and enterohemorrhagic Escherichia coli (EPEC and EHEC). Conclusion: Our study indicates that modern, low-fiber Western diets might make individuals more prone to infection by enteric pathogens via the disruption of the mucosal barrier integrity by characteristic changes in the gut microbiota, illustrating possible implications for EPEC and EHEC infections.