The genetic exchange of antimicrobial resistance determinants among enterococci and staphylococci is well documented. The resistance genes are typically found on conjugative plasmids or transposons. One requirement for the conjugative transfer of mobile genetic elements is cell-to-cell contact between donor and recipient. To facilitate this contact, enterococci have highly evolved conjugative systems that are responsible for the dissemination of antimicrobial resistance and virulence factors. These systems include the secretion of bacterial sex pheromones, small peptides that induce a mating response resulting in the aggregation or clumping of the cells. Cell-to-cell contact occurs naturally in microbial biofilms. Microbial cells attached to a surface produce an extracellular polymeric substance that supports a highly structured microbial community. Cells within this matrix have increased tolerance to antimicrobial agents, making it difficult or impossible to eradicate the biofilm once it becomes established. Many species of microorganisms colonize and form biofilms on a variety of indwelling medical devices…….