Credit: D. SCHARF/SCIENCE FACTION/CORBIS

J. Exp. Med. doi:10.1084/jem.20090097 (2009)

A bacterium that causes many skin and bloodborne infections and the bacterium responsible for anthrax both synthesize the same molecule to evade host immune responses.

Olaf Schneewind and his colleagues at the University of Chicago in Illinois examined the ability of Staphylococcus aureus (pictured) to survive in rodent blood. They found that an enzyme anchored to the bacterium's cell wall produces adenosine, a key signalling molecule, during infection to protect the bacteria from attack by white blood cells. The anthrax pathogen Bacillus anthracis uses the same mechanism for survival.