The PavA-Like Fibronectin-Binding Protein of Enterococcus faecalis, EfbA, is Important for Virulence in a Mouse Model of Ascending Urinary Tract Infection

Enterococcus faecalis is an established nosocomial pathogen, yet the pathogenesis of enterococcal infections remains to be fully elucidated, particularly of urinary tract infections (UTIs). Fibronectin-binding proteins have been identified as potent adhesins in pathogenic Gram-positive cocci. Here, we characterized EfbA, which is encoded by the enterococcal orthologue of Streptococcus pneumoniae pavA. Similar to PavA, the anchorless EfbA protein was localized to the enterococcal cell outer surface and bound to immobilized human fibronectin. In addition to abrogate EfbA expression, deletion of the efbA gene eliminated EfbA from the cell surface and drastically reduced the enterococcal cell binding to immobilized fibronectin. The ΔefbA deletion mutant was highly attenuated versus wild-type in a murine ascending UTI model, consistent with an increased tropism for the kidney relative to the bladder. These results provide the first evidence that EfbA of E. faecalis plays a role in UTI, probably contributing to the pathogenesis in this site.