The infectious intracellular lifestyle of Salmonella enterica relies on the adaptation to nutritional conditions within the Salmonella-containing vacuole

ABSTRACTSalmonella enterica serovar Typhimurium (S. Typhimurium) is a Gram-negative pathogen that causes various host-specific diseases. During their life cycle, Salmonellae survive frequent exposures to a variety of environmental stresses, e.g. carbon-source starvation. The virulence of this pathogen relies on its ability to establish a replicative niche, named Salmonella-containing vacuole, inside host cells. However, the microenvironment of the SCV and the bacterial metabolic pathways required during infection are largely undefined. In this work we developed different biological probes whose expression is modulated by the environment and the physiological state of the bacterium. We constructed transcriptional reporters by fusing promoter regions to the gfpmut3a gene to monitor the expression profile of genes involved in glucose utilization and lipid catabolism. The induction of these probes by a specific metabolic change was first tested in vitro, and then during different conditions of infection in ma...