A rabbit model for Staphylococcus aureus osteomyelitis was used to compare treatment with clindamycin and cefazolin. Cefazolin (5 mg/kg), cefazolin (15 mg/kg), and clindamycin (70 mg/kg) were injected subcutaneously every 6 h for 28 days. After treatment, S. aureus was found in bone cultures from 22 of 23 control rabbits, 12 of 22 rabbits treated with cefazolin (5 mg/kg), 12 of 23 rabbits treated with cefazolin (15 mg/kg), and 2 of 20 rabbits treated with clindamycin. Drug concentrations in serum, uninfected bone, and infected bone were measured 30 mim after cefazolin or clindamycin was injected into a group of rabbits which had been infected for 3 to 4 weeks. Clindamycin gave the highest concentration in infected and uninfected bone. The results of the study showed that clindamycin was superior to cefazolin in the eradication of S. aureus from infected bone in an experimental model.

A rabbit model for Staphylococcus aureus osteomyelitis was used to compare the results of treatment with A-56619 and A-56620, two new aryl-fluoroquinolones, and nafcillin. A-56619 (15 mg/kg) and A-56620 (20 mg/kg), both used for 28 days of treatment, were injected subcutaneously every 12 h, and nafcillin (40 mg/kg) was injected every 6 h. After treatment, S. aureus was found on bone marrow cultures from 19 of 20 control rabbits, 6 of 20 treated with A-56619, 14 of 20 treated with A-56620, and 8 of 20 treated with nafcillin. Drug concentrations in serum and uninfected and infected bone were measured 1 h after A-56619 and A-56620 itjection and 30 min after nafcillin injection in a group of rabbits that had been infected for 3 to 4 weeks. The concentrations in infected bone were similar for all three drugs and were significantly higher than in uninfected bone. The results of this study showed that A-56619 had a high rate of eradication of S. aureus from infected bone and compared favorably to nafcillin.