FIG 1.

Model showing how VRE genetic plasticity may lead to intestinal domination and invasive infection. Brown curved lines indicate the mucosal surface of the gastrointestinal (GI) tract, and light-yellow shading depicts the associated mucus layer. The right-most portion highlights inflammatory changes that can occur at the GI mucosal surface in times of illness, which can lead to a breakdown of innate host defenses. Black horizontal arrows are labeled with examples of external selective pressures, such as antibiotic exposure and altered enteral nutrition. Curved arrows highlight genetic adaptations that can occur during selection to generate a population of enterococci (purple ovals) that resists eradication and outcompetes other enteric commensal bacteria (depicted by multicolored shapes).