Isolation and characterization of a capsular polysaccharide adhesin from Staphylococcus epidermidis

We isolated a polysaccharide adhesin from Staphylococcus epidermidis strain RP-62A. The adhesin was composed of a complex mix of monosaccharides (with galactose and glucosamine predominating), bound well to silastic catheter tubing, inhibited adherence of strain RP-62A to catheters, and elicited antibodies that both blocked adherence and stabilized an extracellular structure (visualized by transmission electron microscopy) that appeared to be a capsule. Two of three heterologous, highly adherent strains of coagulase-negative staphylococci also produced this adhesin, and their adherence to catheters was inhibited by both purified adhesin and antibody to adhesin. In contrast, the adherence of one highly adherent and two poorly adherent heterologous strains was unaffected by the RP-62A purified adhesin or antibody, a result suggesting the expression of alternate adhesins by these strains. We conclude that the capsular polysaccharide of some strains of coagulase-negative staphylococci is an important factor in adherence to catheter tubing.