Enterococcus faecalis

Enterococcus faecalis is a gram-positive bacterium that is a normal inhabitant of the human gastrointestinal tract, but it is also a well-documented opportunistic pathogen associated with nosocomial (hospital-acquired) infections, dental root canal persistence, and antibiotic resistance, including vancomycin-resistant strains. The research record for this undesignated species entry is dominated by studies of pathogenic and resistance mechanisms, including biofilm formation, metalloprotease activity documented in relation to intestinal barrier integrity, and mobile genetic elements that spread antibiotic resistance genes. Certain specific strains of E. faecalis have been commercialized as probiotics historically, but the species as a whole carries recognized safety concerns, and regulatory agencies in Europe have moved toward restricting its use in probiotic products without comprehensive safety evaluation. This entry is described here in a taxonomic and research context; it is not established as safe or effective for general probiotic use. These are research topics, not findings; the papers do not establish that this strain treats or prevents any condition.