Salmonella persisters undermine host immune defenses during antibiotic treatment

Actively persistent Salmonella A proportion of Salmonella cells can enter a reversible state of growth arrest, which allows them to tolerate environmental stress such as antibiotics. Stapels et al. found that these cells are not dormant but are actively modulating their environment. Salmonella within their host macrophage niche deployed a specialized type 3 secretory system called SPI-2 to deliver virulence factors, including SteE, into host cells. SteE changed the cytokine profile of the infected macrophages to reprogram them into a noninflammatory and infection-permissive state. Thus, when antibiotics were removed, the Salmonella could reemerge and cause disease. Science , this issue p. 1156