Secreted Proteins and Virulence in Salmonella enterica
from: Bacterial Secreted Proteins: Secretory Mechanisms and Role in Pathogenesis (Edited by: Karl Wooldridge). Caister Academic Press, U.K. (2009)
Secreted proteins are of major importance for the pathogenesis of infectious diseases caused by the facultative intracellular gastrointestinal pathogen Salmonella enterica. A remarkable large number of fimbrial and non-fimbrial adhesins are present in Salmonella and mediate biofilm formation as well as the intimate contact to host cells. The host cell invasion and intracellular proliferation are two hallmarks of Salmonella pathogenesis. Salmonella deploys two type III secretion systems (T3SS) to translocate complex cocktails of effector proteins. Effectors translocated by the Salmonella Pathogenicity Island 1 (SPI1)-T3SS mainly act on the host cell actin cytoskeleton resulting in the invasion of non-phagocytic cells. After entry, Salmonella resides in the so-called Salmonella-containing vacuole, from which translocation of a second set of effector proteins by the SPI2-T3SS initiated. The function of the SPI2-T3SS results intracellular replication and the modification of host cell vesicular traffic involving microtubules. Although classical exotoxins are not known as major virulence determinants of Salmonella, recent data suggest a role of toxins encoded by the Salmonella virulence plasmid. The concerted action of various secreted proteins allows Salmonella to breach multiple barriers of host defense resulting in systemic infection and be development of a carrier state in some infected individuals read more ...