title: An 18 kDa scaffold protein is critical for Staphylococcus epidermidis biofilm formation.
abstract: Virulence of the nosocomial pathogen Staphylococcus epidermidis is crucially linked to formation of adherent biofilms on artificial surfaces. Biofilm assembly is significantly fostered by production of a bacteria derived extracellular matrix. However, the matrix composition, spatial organization, and relevance of specific molecular interactions for integration of bacterial cells into the multilayered biofilm community are not fully understood. Here we report on the function of novel 18 kDa Small basic protein (Sbp) that was isolated from S. epidermidis biofilm matrix preparations by an affinity chromatographic approach. Sbp accumulates within the biofilm matrix, being preferentially deposited at the biofilm-substratum interface. Analysis of Sbp-negative S. epidermidis mutants demonstrated the importance of Sbp for sustained colonization of abiotic surfaces, but also epithelial cells. In addition, Sbp promotes assembly of S. epidermidis cell aggregates and establishment of multilayered biofilms by influencing polysaccharide intercellular-adhesin (PIA) and accumulation associated protein (Aap) mediated intercellular aggregation. While inactivation of Sbp indirectly resulted in reduced PIA-synthesis and biofilm formation, Sbp serves as an essential ligand during Aap domain-B mediated biofilm accumulation. Our data support the conclusion that Sbp serves as an S. epidermidis biofilm scaffold protein that significantly contributes to key steps of surface colonization. Sbp-negative S. epidermidis mutants showed no attenuated virulence in a mouse catheter infection model. Nevertheless, the high prevalence of sbp in commensal and invasive S. epidermidis populations suggests that Sbp plays a significant role as a co-factor during both multi-factorial commensal colonization and infection of artificial surfaces.
authors: Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Hamburg, Germany.
authors: Rahel
authors: R
authors: Decker
authors: Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Hamburg, Germany.
authors: Christoph
authors: C
authors: Burdelski
authors: Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Hamburg, Germany.
authors: Melanie
authors: M
authors: Zobiak
authors: Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Hamburg, Germany.
authors: Henning
authors: H
authors: Büttner
authors: Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Hamburg, Germany.
authors: Gefion
authors: G
authors: Franke
authors: Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Hamburg, Germany.
authors: Martin
authors: M
authors: Christner
authors: Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Hamburg, Germany.
authors: Katharina
authors: K
authors: Saß
authors: UKE Microscopy Imaging Facility, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany.
authors: Bernd
authors: B
authors: Zobiak
authors: Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Hamburg, Germany.
authors: Hanae A
authors: HA
authors: Henke
authors: Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America.
authors: Alexander R
authors: AR
authors: Horswill
authors: Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum des Saarlandes, Homburg, Germany.
authors: Markus
authors: M
authors: Bischoff
authors: Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum des Saarlandes, Homburg, Germany.
authors: Stephanie
authors: S
authors: Bur
authors: Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum des Saarlandes, Homburg, Germany.
authors: Torsten
authors: T
authors: Hartmann
authors: Department of Pathology and Microbiology, Center for Staphylococcal Research, University of Nebraska Medical Center, Omaha, Nebraska, United States of America.
authors: Carolyn R
authors: CR
authors: Schaeffer
authors: Department of Pathology and Microbiology, Center for Staphylococcal Research, University of Nebraska Medical Center, Omaha, Nebraska, United States of America.
authors: Paul D
authors: PD
authors: Fey
authors: Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Hamburg, Germany.
authors: Holger
authors: H
authors: Rohde
mesh_terms: D000818:Animals; D001422:Bacterial Adhesion / Q000502:physiology*; D018441:Biofilms / Q000254:growth & development*; D051379:Mice; D033902:Periplasmic Binding Proteins / Q000235:genetics / Q000378:metabolism*; D013212:Staphylococcus epidermidis / Q000502:physiology*
chemical_list: D033902:Periplasmic Binding Proteins; C044773:sulfate-binding protein, bacteria