Abstract: AIM: To develop tissue cage infection model and study the efficacy of levofloxacin in treatment of staphylococcus aureus infection.METHODS: A plastic ball was implanted into each rabbit through a dorsal midline incision under aseptic conditions.By 4 weeks after implantation, each plastic ball had filled with clear, yellowish tissue fluid.To develop tissue cage infection model, staphylococcus aureus culture was injected into each preimplanted plastic ball.Rabbits were administered levofloxacin at different dose once daily by use of a gavage feeding tube.Tissue cage fluid was taken out from the plastic ball, and concentration of bacteria and loss of susceptibility were monitored in tissue cage fluid.RESULTS: Levofloxacin at 5 mg/kg caused bacterial numbers to decrease throughout treatment.Doses of levofloxacin at 10 or 20 mg/kg reduced bacterial numbers for the first 3 days, but bacterial growth was observed during late stage of treatment and during post-treatment observation. Levofloxacin at 40 mg/kg caused bacterial numbers to decrease throughout treatment and to remain low level during the growth recovery period.Dose of levofloxacin at 5 or 10 or 20 mg/kg caused the loss of susceptibility easily, but no resistance occurred at dose of 40 mg/kg.CONCLUSION: The bacterial response and occurrence of resistance depend on the levofloxacin dose.

Key words: rabbit, tissue cage infection model, staphylococcus aureus, levofloxacin