Figure 1.

Prominent Yersinia virulence factors. Yersinia pestis and enteropathogenic Y. pseudotuberculosis and Y. enterocolitica vary greatly in their pathogenicity and in aspects of their pathogenesis. This is reflected by the different repertoire of proven and potential virulence factors in their respective armories. In particular, Y. pestis has acquired additional plasmid DNA that encodes for factors that enable colonization and transmission via the flea vector and survival in blood. It is also apparent that the regulatory circuitry of Y. pestis has been rewired in ways that drive elevated in vivo expression of critical virulence associated factors. On the flip side, Y. pestis has lost flagella-mediated motility and cell-adhesive capacities that are otherwise critical for survival of the enterics both in the environment and in the GI tract, respectively. Yet commonalities between all three pathogens exist, such as the prominent virulence plasmid-encoded Ysc-Yop type III secretion system responsible for promoting an extracellular infection niche, along with other systems responsible for distributing de novo synthesized proteins into other extracytoplasmic compartments or even realized free from the bacteria.