Oral cavity infection by Enterococcus faecalis: virulence factors and pathogenesis

Abstract

Enterococcus faecalis plays an important role in human oral cavity infections and may be one of the important species in endodontic treatment failure. In this review article, we provide an overview on the occurrence of the virulence factors associated with E. faecalis in oral infections. Seven virulence factors of E. faecalis have been associated with oral infections including extracellular surface protein (esp), gelatinase (GelE), aggregation substance (Asa), adhesion of collagen from E. faecalis (Ace), Serine protease (Spr), lipoteichoic acid (LTA) and E. faecalis antigen A (efaA). The absence of these factors leads to depletion of strains in attachment and biofilm formation procedure in oral infections. The virulence factors facilitate adherence, colonization and resistance of organisms against the host immune response. Each of the virulence factors may be associated with various stages of infection. Some products of the bacteria may be directly linked to damaging of the host tissues; most of the tissue damage is probably mediated by the host response to the bacteria and its products. Our knowledge regarding exact pathogenic factors is incomplete but it seems to be a sophisticated and tangled mechanism. Developing immunization against virulence factors of E. faecalis might be one of the effective prophylactic tool to prevent chronic infections in oral, dental and other sites of the body, such as endocardia.