The diffusion of pefloxacin into bone and the treatment of osteomyelitis

Pefloxacin was evaluated in the treatment of bone infections. A clinical trial was performed in 15 patients with chronic osteitis (5 Staphylococcus aureus, 5 Pseudomonas aeruginosa, 3 Serratia sp., 1 Proteus mirabilis, and a mixed infection with a Streptococcus faecalis and Escherichia coli). Patients were given pefloxacin 400 mg 12-hourly iv for 48 h followed by oral treatment. Bone biopsies from the iliac crest were carried out after at least seven days treatment, 2 h after the last dose. Serum levels were estimated at the same time. In 13 patients the pefloxacin levels were between 2 and 10 mg per g of bone and always greater than, or equal to, the MIC for the infecting organism. In 11 patients treated for six months and followed up for up to 14 months after the completion of treatment, the therapy was successful. In another two patients, the results were excellent with closure of fistulae, but there was only limited follow-up. There were two failures: in one (post-radiation osteitis) the infection persisted and in the other there was intolerance of the antimicrobial. In both cases there was no increase in the MIC of pefloxacin against the organisms. Three patients underwent operations for orthopaedic indications, after at least two months of treatment. Bone cultures from the initial focus remained sterile. Side-effects were mild.