Formerly classified as part of the group D Streptococcus system – 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, where the naturally high levels of antibiotic resistance found in E. faecalis contribute to its pathogenicity.
E. faecalis has been frequently found in root canal-treated teeth in prevalence values ranging from 30% to 90% of the cases.
Root canal-treated teeth are about nine times more likely to harbor E. faecalis than cases of primary infections.
While this normally does not cause disease in the intestine, it can be pathogenic when infecting sites outside of the gut.
In the neurosurgical field, although rare, it can cause brain abscess, subdural empyema, discitis, osteomyelitis, and spinal epidural abscess.
They are one of the pathogens of gas-containing infections in the extremities, such as non-clostridial gas gangrene and necrotizing fascitis.