Shigella infection and host cell death: a double-edged sword for the host and pathogen survival.

In response to bacterial infection, epithelial cells undergo several types of cell death, including apoptosis, necrosis, pyroptosis, and necroptosis, which serve to expel the infected cells and activate the innate and acquired immune responses. Shigella initially invades macrophages and subsequently surrounding enterocytes; the pathogen executes macrophage cell death but prevents epithelial cell death in order to maintain its foothold for replication. To this end, Shigella delivers versatile effector proteins via the type III secretion system (T3SS), allowing it to efficiently colonize the intestinal epithelium. In this article, we review insights into the mechanisms underlying circumvention of the host cell death by Shigella, as an example of bacterial fine-tuning of host cell death pathways.