Study On Influence Of Heparin On Bacterial Adhesion To Polyvinyl Chloride Segments Used In Cardio-Pulmonary Bypass

Objective: Through observing the differences of bacterial adhesion among polyvinyl chloride segments used in cardio-pulmonary bypass, surface-heparinized polyvinyl chloride segments and polyvinyl chloride segments preincubated for 90 minutes at 37 with 1ml heparin solution (6250u), we will study the influence which heparin molecules either in solution or bound the surface of polyvinyl chloride affect adhesion of Staphylococcus aureus and Staphylococcus epidermidis to such segments so that we can provide beneficial way for the purpose of the prophylaxis of biomaterial centered infection.Methods: S. aureus and S. epidermidis were radiolabelled with 3H-TDR, some polyvinyl chloride (PVC) segments were preincubated for 90 minutes at 37 with 6250u heparin solution, and then making the experiment of bacterial adhesion to PVC , preincubated PVC and surface-heparinized PVC in vitro. The radioactivity associated with these segments was measured with Liquid Scintillation Counting ( -LSC) and the bacterial levels were inferred with according to Counting Per Minute (CPM) of materials. At the sametime, we also use Scanning Electron Microscopy (SEM) to observe thephenomenon of bacterial adhesion to biomaterials.Results:I . Adhesive trial results:l.Surface-heparinized PVC can decrease the binding of S. aureus and S.epidermidis (P < 0.05).2.PVC preincubated with heparin solution can also decrease the binding of S.aureus and S. epidermidis (P < 0.05).3.The number of adhesive S. aureus was lower than that of S. epidermidis ineach of the three PVC group (P < 0.05).II. Scanning Electron Microscopy (SEM) observing results:1.It was found that both S. aureus and S. epidermidis could bind to thesurfaces of all three groups of materials, some bacteria formed microcoloniesand their adhesive sites were nonspecific.2.Bacterial adhesive summit phase was 12-24 hours, during which slimecould be observed.3.The number of bacteria on PVC preincubated with heparin solution andsurface-heparinized PVC was in relatively low levels.Conelusions: The number of S. epidermidis on PVC was greater than that of S. aureus. Both S. aureus and S. epidermidis adhesion were accord with bacterial growth graph, their summit time was 18 hours. Both surface-heparinized PVC and PVC preincubated with heparin solution coulddecrease the binding of the two kinds of bacteria, which told us that PVC modified with heparin could decrease bacterial adhesion in vitro.