Yale University researchers have shed new light how bacteria
like the ones that cause Legionnaires' disease and Q-fever raise
such havoc in human patients. In order to survive, the gram-
negative bacteria use genes that have evolved in tandem with
ones in their hosts to essentially disarm immune system cells
trying to kill them, the scientists report Friday in the journal
Science. "Because of their life style, trying to identify how
these organisms cause disease has been really difficult,'' said
Craig Roy, professor at the Yale School of Medicine in the
section of microbial pathogenesis. Roy and his group described
one innovative way the organisms inflict their damage with
impunity. Some gram-negative pathogens such as Legionella
pneumophila, and Coxiella burnetii, the cause of Q fever,
actually secrete proteins into eukaryotic cells, or cells with a
nucleus. But exactly what those proteins did was not known.
Legionnaires' disease is a dangerous form of pneumonia often
contracted by inhaling water droplets con