In this study, rfaG, luxS, and bcsE gene mutants of S. Typhimurium ATCC 14028 wild-type strain were generated, and their effects on bacterial physiology and pathogenicity were investigated. Biofilm production capacity and mobility of mutant strains were found to be significantly reduced. Immune response stimulation of 6-8 week-old BALB/c mice infected with wild-type and mutants was evaluated on days 0 and 21 for IL-6, IFN-γ, and IgG, and then systemic infection in mice was determined by the amount of Salmonella recovered from the cecum, spleen, and liver organs. The specific IgG antibody level and the expression level of the cytokines IFN-γ and IL-6 were found to be significantly reduced in mice inoculated with mutant strains compared to the control group. The highest level of colonization in the organs was found in the cecum, and the lowest level of colonization was detected in the liver. In the wild-type-infected group, splenomegaly and staining of the liver were detected. In the groups of mice infected with bcsE and luxS mutants, these symptoms were at a low level. In the groups infected with the rfaG mutant, no significant lesions were detected in the organs.