Salmonellae are gram-negative bacteria that cause gastroenteritis and enter
ic fever. Salmonella virulence requires the coordinated expression of compl
ex arrays of virulence factors that allow the bacterium to evade the host's
immune system. All Salmonella serotypes share the ability to invade the ho
st by inducing their own uptake into cells of the intestinal epithelium, In
addition, Salmonella serotypes associated with gastroenteritis orchestrate
an intestinal inflammatory and secretory response, whereas serotypes that
cause enteric fever establish systemic infection through their ability to s
urvive and replicate in mononuclear phagocytes. This review explores the mo
lecular basis of selected Salmonella virulence strategies, with an emphasis
on general themes of bacterial pathogenesis as exemplified by Salmonella.