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Study: Salmonella’s pH Sensors Trigger Virulence

Salmonella bacteria rely on internal pH sensors to initiate their virulent traits after sensing heightened acidity in their environment, according to a study conducted by researchers at the Yale University School of Medicine and the Yale Microbial Diversity Institute.

The findings, published in the June 14 issue of Nature, could someday lead to drugs that disrupt the bacteria’s ability to cause typhoid fever and foodborne illness in humans.

Here’s how the sensors work: When the bacterium senses a change into an acidic environment, it begins producing Adenosine triphosphate (ATP), the “energy currency” for all living cells. This boost of ATP production creates a protein that in turn activates a number of characteristics within the bacterium, including characteristics related to survival and virulence.

“The new insight here is that a change in pH in Salmonella’s surroundings creates increasing ATP inside the Salmonella bacteria,” said Dr. Eduardo Groisman, professor of microbial pathogenesis at the Yale School of Medicine and co-author on the study. “What is affecting it is not necessarily the environment directly, but the consequences of the environment turning acidic.”

While Groisman said there are already teams of researchers working on how to disrupt Salmonella’s pH sensors, he instead plans to look for ways to disrupt the protein created after ATP production gets ramped up inside the bacteria’s host.

The next step, he told Food Safety News, is to figure out exactly what this protein, MgtC, actually does: What does it bind? How is it created in heighted ATP levels?

The answers to those questions could lead to developing a therapeutic drug that treats Salmonella infections, but as Groisman put it, “that’s obviously a long way away.”

The answers could also hold promise for treatments of other pathogens that rely on similar sensors:

“It’s likely that what we find for Salmonella is likely true for other pathogens,” he said, “so that’s a start.”

Read the abstract or order the study on Nature’s website.

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