Infection of epithelial cells with Salmonella enterica

Salmonella enterica serovars cause a variety of diseases ranging from self-limiting gastroenteritis to severe systemic infections. Virulence of these facultative intracellular pathogens is dependent on their ability to invade and replicate within non-phagocytic cells, and cultured epithelial cell systems have been used extensively to dissect the molecular mechanisms involved. For efficient invasion in vitro, the bacterial cell growth conditions as critical since the invasion associated type III secretion system (T3SS1) must be expressed and functional. The ability of Salmonella to invade, and replicate within, epithelial cells can be easily assessed using a gentamicin protection assay or immunofluorescence microscopy. Here, the protocols used in our laboratory are described in detail.