Dietary modulation alters susceptibility to listeria monocytogenes and salmonella typhimurium with or without a gut microbiota

Mathis Wolter, Alex Steimle, Amy Parrish, Jacques Zimmer, Mahesh S. Desai*

*Corresponding author for this work

Research output: Contribution to journalArticleResearchpeer-review

4 Citations (Scopus)


Food safety has considerably improved worldwide, yet infections with foodborne human enteric pathogens, such as Listeria spp. and Salmonella spp., still cause numerous hospitalizations and fatalities. Since dietary alterations, including fiber deficiency, might impact the colonization resistance mediated by the gut microbiome, studying the diet–microbiome–pathogen axis holds promise in further understanding the pathogenesis mechanisms. Using a gnotobiotic mouse model containing a 14-member synthetic human gut microbiota (14SM), we have previously shown that dietary fiber deprivation promotes proliferation of mucin-degrading bacteria, leading to a microbiome-mediated erosion of the colonic mucus barrier, which results in an increased susceptibility toward the rodent enteric pathogen Citrobacter rodentium. Here, we sought to understand how a low-fiber diet affects susceptibility to Listeria monocytogenes and Salmonella enterica serovar Typhimurium by using our 14SM gnotobiotic mouse model in BALB/c and C57BL/6 mouse backgrounds, respectively. Intriguingly, and in contrast to our results with C. rodentium, we observed that depriving mice of dietary fiber protected them from infections with both pathogens, compared to mice fed a standard chow. The microbiome delayed the overall pathogenicity compared to the onset of disease observed in germfree control mice. Nevertheless, we observed the same effect of diet on germfree mice, suggesting that the susceptibility is directly driven by the diet itself even in the absence of the gut microbiome. Our study points out an important observation, namely, that dietary fiber plays a crucial role in either the host’s susceptibility, the virulence of these pathogens, or both. It would be judicious to design and interpret future studies on this basis.

Original languageEnglish
Article numbere00717-21
Pages (from-to)e0071721
Issue number6
Early online date2 Nov 2021
Publication statusPublished - 21 Dec 2021


  • Colonic mucus layer
  • Dietary fiber
  • Gut microbiota
  • Listeria monocytogenes
  • Pathogen susceptibility
  • Salmonella typhimurium


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