How Salmonella survives

Yale scientists have discovered how Salmonella, a bacterium that causes food poisoning and typhoid, escapes the innate immune system’s efforts to destroy it. Typically, bacteria are gobbled up by macrophages, which send bacteria to an execution chamber called a lysozome for degradation.

While they await degradation, Salmonella sit in a holding cell called a vacuole and begin to plan their escape. They secrete a protein, SopB, that changes the composition of the vacuole. This allows the bacterium to escape and find a friendlier compartment where they can replicate and avoid innate immune defenses.

“Salmonella have an elegant strategy for surviving and replicating and avoiding this cellular disposal system,” said Jorge E. Galán, D.V.M., Ph.D., chair of the Section of Microbial Pathogenesis, the Lucille P. Markey Professor of Microbiology and principal investigator of the study published in Science in June. “Our work is revealing a fundamental mechanism by which these bacteria cause disease—and may lead to new targets or strategies for controlling them.”