Prajsnar, T.K., Renshaw, S.A., Ogryzko, N.V., Foster, S.J., Serror, P., and Mesnage, S. (2013) Zebrafish as a novel vertebrate model to dissect enterococcal pathogenesis. Infection and Immunity. 81(11):4271-4279.
Enterococcus faecalis is an opportunistic pathogen responsible for a wide range of life-threatening nosocomial infections such as septicaemia,
peritonitis or endocarditis. E. faecalis infections are associated with a high mortality and substantial healthcare costs and cause therapeutic problems due to the
intrinsic resistance of this bacterium to antibiotics. Several factors contributing to E. faecalis virulence have been identified. Due to the variety of infections caused by this organism, numerous animal models have been
used to mimic E. faecalis infections, but none of them is considered as ideal to follow the pathogenesis. Here, we studied for the first time E. faecalis pathogenesis in zebrafish larvae. Using model strains, chosen isogenic mutants and fluorescent derivatives expressing GFP,
we analyzed both lethality and bacterial dissemination in infected larvae. Genetically engineered immunocompromized zebrafish
allowed the identification of two critical steps for successful establishment of disease: i) host phagocytosis evasion mediated
by the Epa rhamnopolysaccharide and ii) tissue damage mediated by the quorum sensing Fsr regulon. Our results reveal that
zebrafish is a novel, powerful model to study E. faecalis pathogenesis, enabling to dissect the mechanism of enterococcal virulence.