Background and Aims: Many inflammatory diseases are associated with microbial dysbiosis, which may considerably alter the production of short-chain fatty acids (SCFAs). SCFAs are produced in the large bowel through bacterial fermentation of dietary fiber and play an important role in maintaining gut homeostasis. SCFAs, particularly acetate and butyrate, show beneficial immunomodulatory effects contributing to the prevention of inflammatory and allergic reactions. Thus, reduced production of SCFAs may impact on the mucosal immune responses critical to fighting pathogens. This study aims to determine the influence of SCFAs on a murine model of colonic bacterial infection. Methods: In the present study, we used acetate- (HAMSA) or butyrate- (HAMSB) yielding diets to deliver high concentrations of individual SCFAs to the large bowel of mice infected with C. rodentium. We assessed the effects of these SCFAs on clinical burden and gut pathogenicity in correlation with changes in bacteria growth, fecal microbiota composition, function and changes in the immunological profile. Results: Here we show in vitro that acetate and butyrate directly inhibited growth of the attaching and effacing (A/E) pathogen C. rodentium in a bacteriostatic manner. This correlated with reduced expression of Tir, a gene responsible for bacterial adherence and pathogenicity. Interestingly, HAMSA-fed mice presented reduced clinical scores during C. rodentium infection associated with high concentrations of fecal acetate. This was linked with compositional and functional changes in the microbiota when examining 16s sequencing and proteomics analysis. The HAMSA mediated is protection involved increased expression IL-22 and Muc-2 in the colon and increased numbers of CD8αα+ TCRγδ T cells in the colonic epithelium. These effects were dependent on GPR43, a metabolite-sensing GPCR that binds acetate. Conclusions: We established a promising new approach to moderate bacterial gut infections by manipulating the gut microbiota and mucosal immune tolerance through diets that yield the SCFA acetate.