A Salmonella locus that controls resistance to microbicidal proteins from phagocytic cells.

Facultative intracellular pathogens pose an important health problem because they circumvent a primary defense mechanism of the host: killing and degradation by professional phagocytic cells. A gene of the intracellular pathogen Salmonella typhimurium that is required for virulence and intracellular survival was identified and shown to have a role in resistance to defensins and possibly to other microbicidal mechanisms of the phagocyte. This gene may prove to be a regulatory element in the expression of virulence functions.