Prophylaxis of implant-related staphylococcal infections using tobramycin-containing bone cement

In a rabbit model, premixed tobramycin-containing-bone cement was studied f or its efficacy to prevent infections with two frequently encountered staph ylococcal:species in arthroplasty surgery. After intramedullary inoculation with staphylococci, either standard or premixed tobramycin-containing Simp lex-P bone cement was injected in:the right femur of 120 rabbits. Developme nt of infection was-examined by culture of femoral bone after 7 or 28 days. Loss of body weight and elevated erythrocyte sedimentation rate-in the con trol rabbits inoculated with Staphylococcus aureus were seen in the first p ostoperative week, returning to normal in 28 days. Inoculation with Staphyl ococcus epidermidis resulted only in a low-grade infection. All rabbits rec eiving premixed tobramycin-containing bone cement were free of signs of inf ection, and all their cultures were negative. Culture yield from Staphyloco ccus aureus controls increased with time and inoculum dose. Staphylococcus epidermidis controls needed higher inoculum doses to establish an infection , while culture yield decreased in time. These differences in mode of prost hesis-related infection are explained by differences in virulence factors. (C) 2000 John Wiley & Sons, Inc.