PROTAMINE SULFATE AND VANCOMYCIN ARE SYNERGISTIC AGAINST STAPHYLOCOCCUS-EPIDERMIDIS PROSTHESIS INFECTION IN-VIVO

We have previously demonstrated that the quaternary amine, protamine s ulfate (PS), is bactericidal against Staphylococcus epidermidis. In an attempt to decrease genitourinary prosthesis infection rates, we exam ined the ability of PS as a wound irrigant to inhibit Staphylococcus e pidermidis viability. Eighty-seven Sprague-Dawley rats were studied by implanting a sterile silicone pellet in their dorsum. The pellet was inoculated with Staphylococcus epidermidis and the rats were divided i nto four groups based on the wound irrigant employed after inoculation : (I) control (sterile water) (2) vancomycin; (3) PS; (4) vancomycin PS. All rats received perioperative and daily intramuscular vancomyci n, and the pellets were explanted on postoperative day 28 and cultured . The infection rates were: (1) control 77%, (2) vancomycin 50%, (3) p rotamine sulfate 67%, and (4) protamine sulfate and vancomycin 19%. Th e differences between (2) vancomycin versus (4) vancomycin + PS and (3 ) PS versus (4) vancomycin + PS were significant (p = 0.05 and p < 0.0 05). The data suggest that PS potentiates vancomycin as a wound irriga nt in prosthesis implantation