Pathogenicity of Enterococci

This chapter focuses on the pathogenic mechanisms by which enterococci cause human disease. It discusses biology, epidemiology, and environmental persistence of the enterococci. For enterococci to cause disease several barriers must first be overcome. An initial barrier that these organisms confront is the ability to colonize the intestinal tract, where they must compete for nutrient resources in an intestinal milieu including several hundred unique bacterial species. From the site of colonization, the organism must translocate to infectious sites, evade host clearance, and ultimately produce pathologic changes in the host through direct toxic activity, or indirectly by inducing an inflammatory response. Our understanding of how these organisms continually evolve will need to keep pace with their evolution or we may potentially be on the wrong end of a public health nightmare, in which isolates evolve to higher levels of antibiotic resistance and ever increasing virulence.