Specific involvement of pilus type 2a in biofilm formation in group B Streptococcus

• Published in: PloS one 2010-02, Vol.5 (2), p.e9216-e9216
• Main Authors: Rinaudo, Cira Daniela, Rosini, Roberto, Galeotti, Cesira L, Berti, Francesco, Necchi, Francesca, Reguzzi, Valerio, Ghezzo, Claudia, Telford, John Laird, Grandi, Guido, Maione, Domenico
• Format: Article
• Language: English
• Subjects: Aminoacyltransferases - genetics; Aminoacyltransferases - metabolism; Anogenital; Antibodies; Antibodies, Monoclonal - pharmacology; Bacteria; Bacterial Adhesion - drug effects; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Biofilms; Biofilms - drug effects; Biofilms - growth & development; Blotting, Western; Chlamydia pneumoniae; Clinical isolates; Clonal deletion; Coding; Colonization; Conservation; Cysteine Endopeptidases - genetics; Cysteine Endopeptidases - metabolism; Deactivation; Deletion mutant; Epithelial cells; Fimbriae Proteins - genetics; Fimbriae Proteins - immunology; Fimbriae Proteins - metabolism; Fimbriae, Bacterial - chemistry; Fimbriae, Bacterial - classification; Fimbriae, Bacterial - metabolism; Glucose - pharmacology; Health aspects; Humans; Inactivation; Infection; Infectious Diseases; Infectious Diseases/Bacterial Infections; Insertion; Islands; Lactococcus lactis; Meningitis; Microbiology; Microbiology/Immunity to Infections; Microscopy, Confocal; Microscopy, Electron, Scanning; Mucosa; Mutants; Mutation; Neonates; Phenotypes; Pili; Polystyrenes - chemistry; Pseudomonas fluorescens; Sepsis; Solid surfaces; Streptococcal Infections - microbiology; Streptococcus; Streptococcus agalactiae; Streptococcus agalactiae - genetics; Streptococcus agalactiae - physiology; Streptococcus agalactiae - ultrastructure; Streptococcus infections; Streptococcus pyogenes; Sucrose - pharmacology; Surface Properties
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0009216

Streptococcus agalactiae is the primary colonizer of the anogenital mucosa of up to 30% of healthy women and can infect newborns during delivery and cause severe sepsis and meningitis. Persistent colonization usually involves the formation of biofilm and increasing evidences indicate that in pathogenic streptococci biofilm formation is mediated by pili. Recently, we have characterized pili distribution and conservation in 289 GBS clinical isolates and we have shown that GBS has three pilus types, 1, 2a and 2b encoded by three corresponding pilus islands, and that each strain carries one or two islands. Here we have investigated the capacity of these strains to form biofilms. We have found that most of the biofilm-formers carry pilus 2a, and using insertion and deletion mutants we have confirmed that pilus type 2a, but not pilus types 1 and 2b, confers biofilm-forming phenotype. We also show that deletion of the major ancillary protein of type 2a did not impair biofilm formation while the inactivation of the other ancillary protein and of the backbone protein completely abolished this phenotype. Furthermore, antibodies raised against pilus components inhibited bacterial adherence to solid surfaces, offering new strategies to prevent GBS infection by targeting bacteria during their initial attachment to host epithelial cells.