serovar Typhimurium gene is required for intracellular proliferation and virulence.

serovar Typhimurium (. Typhimurium) is one of the most significant zoonotic pathogens that poses a threat to humans. Previous studies have identified that -secreted effector K3 (SseK3) is a novel translated and secreted protein of . Typhimurium. The objective of this study was to determine whether deletion of the gene can attenuate the virulence of . Typhimurium. To do this, we constructed an deletion mutant using the double-exchange allele of the suicide plasmid pRE112Δ and assessed the virulence and intracellular proliferation of the mutant. The deletion mutant exhibited adhesion and invasion properties similar to those of wild-type (WT) . Typhimurium, although the virulence and intracellular proliferation of the mutant were significantly reduced compared to that of the WT strain. Furthermore, the observed increase in the median lethal dose (LD) reflects a decrease in the pathogenicity of the deletion mutant in a murine model. In summary, we concluded that disruption of can attenuate the intracellular proliferation and reduce the virulence of . Typhimurium.