Certain strains of Escherichia coli (E. coli) bacteria can be harmful and cause disease; other strains are harmless and live harmoniously with their host. In fact, harmless strains of E. coli colonize the human intestine shortly after birth and survive there. In contrast, the disease-causing strains produce a wide variety of infections, including meningitis, urinary tract infections and intestinal infections. Enterohaemorrhagic E. coli (EHEC) colonizes the small intestine and induces severe bloody diarrhea. It is a significant cause of illness and death worldwide. EHEC attaches to the surface of cells lining the intestinal walls. These epithelial cells have microvilli, which are small finger-like projections that increase the surface area available to absorb water and nutrients. EHEC causes flattening of microvilli, which enables the bacteria to bind tightly to the intestinal cells and inject effector proteins into the interior of the host cell where they disrupt normal host cell processes and cause disease. Seven novel EHEC effector proteins have been identified and the mechanisms of their function are unknown. In her research, Stephanie Shames is working to identify host proteins in epithelial cells that are targeted by the seven novel EHEC effector proteins and to describe the interaction that occurs between these host and bacterial proteins. This research may provide important insights into how EHEC causes diarrhea which, in turn, could lead to the development of better methods of treatment and prevention, with world-wide benefits.