| With over 200 million intravascular devices sold annually in the United States, it is apparent that biomedical devices have become an integral part of clinical medicine, and their use is increasing continuously. It has been estimated that over 45% of all hospital infections are related to implants and medical devices. The adherence of bacteria to the biomaterial surface may be the critical event in the pathogenesis of implant-induced infection. Investigations have revealed that bacterial adhesion to artificial surfaces is affected by blood components. This project was designed to examine the effect of certain blood elements on the adhesion of three strains of bacteria, Staphylococcus epidermidis, Staphylococcus aureus, and Pseudomonas aeruginosa to biomaterials. Fibrin and activated platelets were immobilized on polyurethane Tecoflex® surfaces, and it was noted that the presence of fibrin and/or platelets deposits on the surface significantly increased the adhesion of Staphylococcus epidermidis and Pseudomonas aeruginosa. Scanning electron microsocopy evaluation of surfaces revealed specific adhesion of bacteria to surface-bound fibrin.; Whereas fibrin and platelets promoted bacterial adhesion, the presence of serum in the medium resulted in the inhibition of bacterial adhesion. These observations prompted a systematic investigation of the effect of serum proteins on bacterial adhesion. Serum was fractionated by anion-exchange chromatography and various protein pools were examined for their effect on bacterial adhesion. Apo-transferrin was identified as the inhibitory component of serum. Upon removal of transferrin from human serum, most of the inhibitory activity of serum, in regards to bacterial adhesion, was greatly diminished. Data presented herein suggest that apo-transferrin, by binding to bacterial surface in the fluid phase, prevents their adhesion to biomaterials surfaces. Transmission electron microscopy revealed no noticeable changes in the ultrastructural features of the bacterial membrane. Furthermore, it was shown that deglycosylation of apo-transferrin does not interfere with its inhibitory activity with respect to bacterial adhesion to biomaterials.; Challenges remain in defining the underlying molecular mechanisms of apo-transferrin interaction with bacteria, which results in an inhibition of bacterial adhesion. Nonetheless, it is reasonable to speculate that an antiadhesive agent, such as apo-transferrin can be exploited in suitable therapeutic interventions with respect to prevention of implant-associated infection. |
