Acid makes bacterium deadly

Salmonella, which kills hundreds of thousands of people each year, turns virulent when it senses that its environment has turned acidic and triggered an increase in its energy level, according to a report in the June 13 issue of the journal Nature by researchers from the School of Medicine and the Yale Microbial Diversity Institute.

This mechanism may present a novel target for drugs that can disarm Salmonella’s ability to cause disease, said Eduardo A. Groisman, Ph.D., professor of microbial pathogenesis and a Howard Hughes Medical Institute investigator. Groisman and associate research scientist Eun-Jin Lee, Ph.D., tracked the signal transduction cascade that enables Salmonella to survive within the host’s immune cells. Changes in the level of acidity raise ATP levels in the bacterium and trigger a key virulence gene.

“There will never be a world without Salmonella because it exists in many, many animal reservoirs,” Groisman said. “It is a major public health issue.”