Dr. Jekyll and Mr. Hide: How Enterococcus faecalis Subverts the Host Immune Response to Cause Infection

Enterococcus faecalis, a ubiquitous member of the healthy human gut microbiota, is also a common opportunistic pathogen and leading cause of nosocomial infections. This tenacious microbe is well adapted to infect and persist in multiple niches within the mammalian host and can rapidly tune its metabolism to respond to new environments, enabling infection in sites including the gastrointestinal tract, urinary tract, wounded epithelium, heart, and blood. In order to withstand and persist in the face of host immune responses, E. faecalis has an arsenal of strategies to suppress, evade, or inactivate innate and adaptive immune mechanisms. In this review, we present the variety of ways E. faecalis modulates the immune response, enabling this otherwise innocuous gut commensal to transition and persist as a pathogen.