title: Functional blocking of Staphylococcus aureus adhesins following growth in ex vivo media.
abstract: Defining the role of Staphylococcus aureus adhesins in disease pathogenesis may depend on the use of bacteria grown in culture media that more closely reflect the human milieu than conventional broth. This study examined the functional effect on S. aureus adhesins following growth in an ex vivo medium containing a complex mixture of human proteins (used peritoneal dialysate) relative to growth in Todd-Hewitt broth. The adherence of S. aureus, cultured in dialysate, to fibronectin and fibrinogen was markedly reduced despite the expresion of full-length ClfA, ClfB, and fibronectin-binding proteins. Growth in dialysate resulted in the acquisition of a surface coat, as visualized by transmission electron microscopy, which was shown to contain fibronectin, fibrinogen, and immunoglobulins. Adherence of S. aureus to fibrinogen following growth in dialysate was significantly reduced by expression of protein A but was restored following growth in immunoglobulin-depleted dialysate. We conclude that bacterial adherence to solid-phase protein is critically dependent on the culture medium, that S. aureus adhesins may become saturated with target protein prior to contact with solid surfaces, and that there is an interaction between fibrinogen-binding proteins and immunoglobulin bound to protein A following contact with host proteins. These findings have important implications for future studies of S. aureus adhesins.
authors.affiliation: Nuffield Department of Clinical Laboratory Sciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom.
authors.forename: Ruth C
authors.initials: RC
authors.lastname: Massey
authors.forename: Shobana R
authors.initials: SR
authors.lastname: Dissanayeke
authors.forename: Brian
authors.initials: B
authors.lastname: Cameron
authors.forename: David
authors.initials: D
authors.lastname: Ferguson
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Foster
authors.forename: Sharon J
authors.initials: SJ
authors.lastname: Peacock
mesh_terms: D018829:Adhesins, Bacterial / Q000502:physiology*; D001422:Bacterial Adhesion / Q000502:physiology*; D001426:Bacterial Proteins / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D003470:Culture Media; D005340:Fibrinogen / Q000378:metabolism; D005353:Fibronectins / Q000378:metabolism; D005798:Genes, Bacterial; D006801:Humans; D007136:Immunoglobulins / Q000378:metabolism; D066298:In Vitro Techniques; D008854:Microscopy, Electron; D011485:Protein Binding; D013205:Staphylococcal Protein A / Q000235:genetics / Q000378:metabolism; D013211:Staphylococcus aureus / Q000235:genetics / Q000254:growth & development / Q000472:pathogenicity* / Q000502:physiology*; D014774:Virulence / Q000502:physiology
chemical_list: D018829:Adhesins, Bacterial; D001426:Bacterial Proteins; D002352:Carrier Proteins; D003470:Culture Media; D005353:Fibronectins; D007136:Immunoglobulins; D013205:Staphylococcal Protein A; D005340:Fibrinogen