Surface protein EF3314 contributes to virulence properties of Enterococcus faecalis.
OBJECTIVE
Identification of putative new virulence factors as additional targets for therapeutic approaches alternative to antibiotic treatment of multi-resistant enterococcal infections.


METHODS
The EF3314 gene, coding for a putative surface-exposed antigen, was identified by the analysis of the Enterococcus faecalis V583 genome for LPXTG-motif cell wall anchor surface protein genes. A non-polar EF3314 gene deletion mutant in the E. faecalis 12030 human clinical isolate was obtained. The wild type and the isogenic mutant strain were investigated for biofilm formation, adherence to Hela cells, survival in human macrophages and a Caenorhabditis elegans infection model. The aminoterminal portion of the EF3314 protein was overexpressed in E. coli to obtain mouse polyclonal antibodies for use in Western blotting and immunolocalization experiments.


RESULTS
The EF3314 gene has an unusually high GC content (46.88% vs. an average of 37.5% in the E. faecalis chromosome) and encodes a protein of 1744 amino acids that presents a series of 14 imperfect repeats of 90 amino acids covering almost the entire length of the protein. Its global organization is similar to the alpha-like protein family of group B streptococci, enterococcal surface protein Esp and biofilm associated protein Bap from S. aureus. The EF3314 gene was always present and specific for E. faecalis strains of human, food and animal origin. Differences in size depended on variable numbers of repeats in the repetitive region.


CONCLUSIONS
EF3314 is a newly described, surface exposed protein that contributes to the virulence properties of E. faecalis.
Creti
Roberta
R
Respiratory and Systemic Disease Unit, Department of Infectious, Parasitic, and Immune-mediated Diseases, National Health Institute (ISS), Rome, Italy. roberta.creti@iss.it
Fabretti
Francesca
F
Koch
Stefanie
S
Huebner
Johannes
J
Garsin
Danielle A
DA
Baldassarri
Lucilla
L
Montanaro
Lucio
L
Arciola
Carla Renata
CR
D000595:Amino Acid Sequence; D000818:Animals; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001482:Base Composition; D018441:Biofilms; D017173:Caenorhabditis elegans; D002473:Cell Wall / Q000378:metabolism*; D004195:Disease Models, Animal; D013293:Enterococcus faecalis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000472:pathogenicity*; D004847:Epithelial Cells / Q000382:microbiology; D015964:Gene Expression Regulation, Bacterial; D016908:Gram-Positive Bacterial Infections / Q000382:microbiology; D006367:HeLa Cells; D006801:Humans; D008264:Macrophages / Q000382:microbiology; D008969:Molecular Sequence Data; D009154:Mutation; D013997:Time Factors; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism*
D001426:Bacterial Proteins; D037521:Virulence Factors