CONDITIONING FLUID INFLUENCES ON THE SURFACE-PROPERTIES OF SILICONE AND POLYURETHANE PERITONEAL CATHETERS - IMPLICATIONS FOR INFECTION

Catheter-related infection remains a considerable problem in continuou s ambulatory peritoneal dialysis (CAPD). This study examined the adher ence of clinical isolates of Staphylococcus epidermidis to commerciall y available polyurethane and silicone peritoneal catheters in the pres ence and absence of a proteinaceous conditioning film. In addition, th e effects of the conditioning film on the surface properties (advancin g and receding contact angles, and surface rugosity) of these biomater ials were investigated. Bacterial adherence to polyurethane and silico ne catheters, pre-treated with phosphate-buffered saline (PBS) or arti ficial spent peritoneal dialysate (ASD) for 1 h at 37 degrees C, was e xamined using a radiometric (2-H-3-adenine) adherence assay. The advan cing and receding contact angles and the surface rugosity of ASD- and PBS-treated biomaterials were examined using a dynamic contact angle a nalyser and an atomic force microscope, respectively. The bacterial is olates were selected to represent high and low cell surface hydrophobi city. The hydrophobic isolate exhibited both a significantly greater r ate and a significantly greater extent of adherence than the hydrophil ic isolate to both catheter materials, independent of pre-treatment. I n general, pre-treatment of the catheter materials with ASD significan tly decreased the subsequent adherence of both isolates owing to the d eposition of a conditioning film on the surface of the biomaterial. AS D treatment also decreased both the advancing and receding contact ang les and the surface rugosity of both catheter materials. This study hi ghlights the influence of both bacterial cell surface hydrophobicity a nd biomaterial surface conditioning films on bacterial adherence to CA PD catheters. In addition, it is recommended that the effects of prote inaceous conditioning films on biomaterial surface properties should b e considered when assessing materials for medical devices and products .