Exploring the Role of Enterococcus faecalis in Oral Infections: A Comprehensive Literature Review

Abstract

Enterococcus faecalis is a Gram-positive facultative anaerobe that can function as both a commensal organism and an opportunistic pathogen. Its capacity to survive nutrient deprivation, alkaline conditions, oxidative stress, antimicrobial exposure, and biofilm-associated environments contributes to its persistence in oral infections, particularly recurrent endodontic disease. This review synthesises the role of E. faecalis in oral infections, with emphasis on virulence factors, biofilm formation, antimicrobial resistance, diagnostic challenges, treatment strategies, environmental and host influences, and future research priorities. The review considers mechanisms including cytolysin production, aggregation substances, gelatinase activity, dentinal tubule penetration, and resistance associated with biofilm growth. It also examines the organism’s reported involvement in endodontic infections, periodontal disease, peri-implantitis, and oral abscesses. Conventional culture-based diagnosis is considered alongside PCR, qPCR, imaging methods, and next-generation sequencing. Current management approaches include mechanical instrumentation, sodium hypochlorite, chlorhexidine, and intracanal medicaments, while emerging approaches include bacteriophage therapy, antimicrobial peptides, probiotics, nanoparticle-based systems, light-activated therapies, and computational drug discovery. Persistent infection remains difficult to manage because multiple survival and resistance mechanisms operate concurrently. Further work should prioritise precise diagnosis, targeted antibiofilm strategies, improved delivery into dentinal tubules, and careful evaluation of emerging interventions under clinically relevant oral conditions and treatment scenarios.