Characterization of a proteinaceous adhesin of Staphylococcus epidermidis which mediates attachment to polystyrene.

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RESUMO

Coagulase-negative staphylococci (CoNS) have evolved into important agents of foreign body-related infections. Adhesion of causative bacteria to biomaterials is considered to be an essential step in these infections. We and others have shown that adhesion of CoNS to biomaterials may be mediated by protease-sensitive surface constituents. In the present study we expanded on these investigations by characterizing a biomaterial adhesin of Staphylococcus epidermidis 354 by using a strain-specific monoclonal antibody (MAb 36.4). MAb 36.4 was strongly and exclusively reactive with strain 354 in an enzyme-linked immunosorbent assay in which whole bacteria were used as antigens. Immunoblotting of cell wall polypeptides of strain 354 revealed strong reactivity with a 200- to 220-kDa band and a weaker reaction in the 100- to 110-kDa range. Preincubation of strain 354 with MAb 36.4 resulted in a 54 to 91% (mean +/- standard deviation, 74% +/- 14%; n = 10) inhibition of adhesion to polystyrene spheres. Fab fragments prepared from MAb 36.4 also inhibited adhesion effectively, indicating specific blocking of an adhesion antigen rather than aspecific inhibition. Immunogold electron microscopy with MAb 36.4 revealed deposition of gold particles on the cell surface and possibly also on fimbrialike surface projections. It is concluded that a surface-located protein antigen of S. epidermidis 354 recognized by MAb 36.4 acts as an adhesin mediating attachment to uncoated foreign material. It is speculated that this type of adhesion to biomaterials may play an important role in the pathogenesis of foreign body-related infections caused by CoNS.

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