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Spring 2012
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Around the Quad

Researchers Discover a Compound That Controls Listeria

By Krishna Ramanujan

In a year when cantaloupe tainted with Listeria monocytogenes killed 30 people, the discovery of a compound that controls this deadly bacterium—and possibly others—is great news.

Cornell researchers have identified a compound called fluoro-phenyl-styrene-sulfonamide (FPSS) that is safe for mammals but stops Listeria in its tracks. The discovery, reported in the November/December issue of mBio, was made by Kathryn Boor, professor of food science and the the Ronald P. Lynch Dean of the College of Agriculture and Life Sciences; Mary Elizabeth Palmer, Ph.D. ’10; Soraya Chaturongakul, Ph.D. ’06; and Martin Wiedmann, Ph.D. ’97, professor of food science.

For a foodborne pathogen like Listeria to infect a human, it must be able to survive rapid changes in its environment, from the cold of refrigeration to the heat of cooking and from the highly acidic stomach to the anaerobic conditions of the small intestines.

“We were the first to characterize the molecular linchpin—called sigma B—in the transition of this organism from a harmless environmental microbe to a human pathogen,” Boor said. “It allows these single-celled pathogens to survive environmental assaults associated with transmission in foods, followed by transit in the human body.”

In a screen of 57,000 natural and synthetic small compounds, they found that FSPP inhibited sigma B in both Listeria and Bacillus subtilis, a soil bacterium and food contaminant that survives high heat.

FPSS interrupts a mechanism that controls the genes that are switched on when the bacterium experiences a rapid change in its environment.

FPSS is non-toxic to humans and eventually may be developed as a drug to combat listeriosis and other bacterial infections.