ADHESION OF STAPHYLOCOCCI TO POLYURETHANE AND HYDROGEL-COATED POLYURETHANE CATHETERS ASSAYED BY AN IMPROVED RADIOLABELING TECHNIQUE

Adhesion of Staphylococcus epidermidis NCTC 11047 to the external surf ace of polyurethane catheters was quantified by a radiolabelling assay . Maximum adhesion was achieved with an initial cell concentration of 3 x 10(8)/ml after incubation for 120 min. The assay was tested for re producibility by analysis of variance. Adhesion of clinical strains of S. epidermidis and S. aureus to uncoated polyurethane and hydrogel (H ydromer(R))-coated polyurethane catheters was compared. Hydrogel coati ng significantly reduced adhesion for both S. epidermidis and S. aureu s (mean percentage reduction 71 % for S. epidermidis, 69 % for S. aure us). Clinical isolates were also tested for adhesion to polystyrene by a modified microtitration well adhesion assay; there was no correlati on between staphylococcal adhesion to polyurethane catheters and adhes ion to polystyrene. Cell surface hydrophobicity values varied widely f or both species. Positive correlations were found between cell surface hydrophobicity and adhesion to polystyrene and uncoated polyurethane catheters for S. epidermidis but not for S. aureus.