Insights into the interaction of Enterococcus faecalis with host cells

Enterococcus faecalis is a core member of the human gut microbiota. Harmless for healthy humans, it is able to cause disease in susceptible patients under antibiotic-induced microbiota alteration. Nowadays, E. faecalis ranks as the third cause of nosocomial infections worldwide. E. faecalis pathogenicity is a multifactorial process but the cellular mechanisms of its interaction with the host remain poorly understood. Using cellular models of infection and in vivo models, we aimed to characterize the role of the virulence factor ElrA during cellular infection. Our goal was also to determine if FHL2, an ElrA eukaryotic partner, was implicated in E. faecalis infection and the impact of ElrA-FHL2 interaction. We have demonstrated that ElrA acts as an invisibility cloak allowing E. faecalis to avoid macrophage recognition. Also, we have shown that FHL2 is implicated in the defense against E. faecalis infection, involving partially ElrA. In parallel, we showed that intracellular replication of E. faecalis in hepatic cells. Altogether, our work provides new insights in E. faecalis interactions with the host cell.