Staph and A Secret Weapon

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Researchers are getting closer to understanding the workings of Staphylococcus aureus, a bacterium that causes more than 60,000 infections each year. And that could lead to better treatment for the infections.

The bacterium, S. aureus, is often a harmless organism found in the nose and skin of 30 percent of people. But it can cause serious infections if it gets into deeper tissues.

Until now, researchers haven’t been sure how that harmful procedure happens. But Biochemists from Kansas State University have found that a family of proteins — extracellular adherence proteins, or Eaps — helps the bacterium do its damage.

In their latest research, Brian Geisbrecht, professor of biochemistry and molecular biophysics, and Kasra Ramyar, his research associate, discovered that S. aureus secretes Eaos, which can shut down neutrophil serin proteases, or NSPs, the most abundant type of white blood cells. Normally, NSPs would protect the body from infection.

“Neutrophils are like the fire department of the immune system,” Geisbrecht said. “They are the first on the scene when a microbial infection tries to take hold. To our knowledge, Staph is the first example of any bacterium that secretes protease inhibitors specifically to block…the immune response,” Geisbrecht said. “Understanding this interaction can not only help us design better therapies in the future, but may help make current treatment regimens work better.”

The findings were published in the Proceedings of the National Academy of Sciences.