Eat in or Take out? Metabolism of Intracellular Salmonella enterica

Salmonella enterica is an important gastrointestinal and facultative intracellular pathogen. After invasion of host cells, it resides in a specialized, replication-permissive compartment, the Salmonella-containing vacuole (SCV). During maturation of the SCV, Salmonella remodels the host endosomal system to form a variety of membranous extensions from the SCV, one type designated Salmonella-induced filaments (SIFs). It was long unclear how Salmonella is able to sustain replication within the SCV, thought to be a nutrient-poor environment. Recent studies started to characterize the metabolic pathways used by intracellular Salmonella. Besides, new insights into the ultrastructure and biogenesis of SIFs and their essential role in nutrition were obtained lately. Here, we review the recent progress with focus on observations gained by various cellular models.