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

The change of dietary habits in Western societies, including reduced consumption of fiber, is linked to alterations in gut microbial ecology. Nevertheless, mechanistic connections between diet-induced microbiota changes that affect colonization resistance and enteric pathogen susceptibility are still emerging. We sought to investigate how a diet devoid of soluble plant fibers impacts the structure and function of a conventional 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, microbiome-mediated 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 low-fiber diet-induced 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, respectively). Our study indicates that modern, low-fiber Western-style diets might make individuals more prone to infection by enteric pathogens via the disruption of mucosal barrier integrity by diet-driven changes in the gut microbiota, illustrating possible implications for EPEC and EHEC infections.

西方社会饮食习惯的改变，包括纤维摄入量的减少，与肠道微生物生态的改变有关。然而，饮食诱导的微生物群变化影响定植抗性和肠道病原体易感性之间的机制联系仍在不断涌现。我们试图研究缺乏可溶性植物纤维的饮食如何影响无特定病原体（SPF）小鼠常规肠道微生物群的结构和功能，以及这些变化如何改变对一种啮齿动物肠道病原体的易感性。我们发现，膳食纤维摄入的缺失导致特定分类群丰度的改变、微生物群介导的结肠黏液屏障侵蚀、促进肠道屏障的短链脂肪酸减少，以及黏膜屏障完整性破坏的标志物增加。重要的是，我们的研究结果强调，肠道微生物生态中这些由低纤维饮食诱导的变化共同导致了黏膜病原体柠檬酸杆菌引起的致命性结肠炎，柠檬酸杆菌被用作肠道致病性和肠出血性大肠杆菌（分别为EPEC和EHEC）的小鼠模型。我们的研究表明，现代的低纤维西式饮食可能通过肠道微生物群因饮食驱动而发生的变化破坏黏膜屏障完整性，使个体更容易受到肠道病原体的感染，这说明了对EPEC和EHEC感染可能产生的影响。