Disease-causing bacteria can develop resistance to antibiotics which are then no longer effective in treating infection, yet they also have another tactic to avoid being killed off by antibiotic treatment. Some cells of the population quietly hide in a dormant state and wait for the danger to subside. Then they return to full function. For example, some urinary tract infections flare up again even after apparently successful treatment with antibiotics. Maja Semanjski, Katrin Bratl and Andreas Kiessling, led by Professor Boris Maček of the University of Tübingen’s Proteom Centrum, and in collaboration with Elsa Germain and Professor Kenn Gerdes of the University of Copenhagen, have investigated such persistent forms of E. coli bacteria. Variations of an enzyme indicated which processes initiate the dormant state. This provides the researchers with possible starting-points at which to seek active substances to combat the dormant cells. The study is published in the latest edition of Science Signaling