Enterococcus faecalis

Enterococcus faecalis is a Gram-positive commensal bacterium inhabiting the gastrointestinal tracts of humans and other mammals. Like other species in the genus Enterococcus, E. faecalis can cause life-threatening infections in humans, especially in the nosocomial (hospital) environment: the naturally high levels of antibiotic resistance found in E. faecalis contribute to its pathogenicity.

Pathogenesis
E. faecalis can cause endocarditis, as well as bladder, prostate, and epididymal infections; nervous system infections are less common.

E. faecalis is resistant to many commonly used antimicrobial agents (aminoglycosides, aztreonam, cephalosporins, clindamycin, the semi-synthetic penicillins nafcillin and oxacillin, and trimethoprim-sulfamethoxazole). Exposure to cephalosporins is a particularly important risk factor for colonization and infection with enterococci.

Historical
Prior to 1984, enterococci were members of the genus Streptococcus: thus E. faecalis was known as Streptococcus faecalis.