Tobramycin-containing bone cement and systemic cefazolin in a one-stage revision. Treatment of infection in a rabbit model

The efficacy of tobramycin-containing bone cement with that of systemic cef azolin for treatment of infection in a one-stage revision model is compared . In addition, the value of detecting bacterial DNA after antibiotic treatm ent was Investigated. An implant was inserted into the right tibia of rabbi ts after inoculation with Staphylococcus aureus. At 28 days, the implant wa s removed. Subsequently, either plain bone cement with or without systemic administration of cefazolin, or tobramycin-containing bone cement was injec ted into the medullary canal. The tibiae were cultured 14 days after revisi on (Day 42), and showed a significant decrease In bacterial counts for both antibiotic groups compared with the control group (p less than or equal to 0.05). The rate of infection in the tobramycin-cement group was slightly hi gher (2/9) than in the cefazolin group (0/8), although the difference was n ot significant. Persistence of bacterial DNA after antibiotic treatment may be the result of delayed clearance of DNA and not a sign of active Infecti on. This animal model shows that in a one-stage revision tobramycin-contain ing bone cement can reduce size and rate of infection, although systemic ce fazolin may be more efficacious. Therefore, the use of antibiotic-containin g bone cement combined with systemic antibiotic might provide optimal treat ment. (C) 2001 John Wiley & Sons, Inc.