Virulence Factors in Salmonella Typhimurium: The Sagacity of a Bacterium

Currently, Salmonella enterica Typhimurium (ST) is responsible for most cases of food poisoning in several countries. It is characterized as a non-specific zoonotic bacterium that can infect both humans and animals and although most of the infections caused by this microorganism cause only a self-limiting gastroenteritis, some ST strains have been shown to be invasive, crossing the intestinal wall and reaching the systemic circulation. This unusual pathogenicity ability is closely related to ST virulence factors. This review aims to portray the main virulence factors in Salmonella Typhimurium, in order to better understand the strategies that this pathogen uses to reach the systemic circulation and increase its infectivity in humans and animals. Thus, the most studied Salmonella pathogenicity islands in Salmonella Typhimurium were detailed as to the functions of their encoded virulence factors. In addition, available knowledge on virulence plasmid was also compiled, as well as the chromosome regions involved in the virulence of this bacterium.