STAPHYLOCOCCAL OSTEOMYELITIS - A COMPARISON OF CO-AMOXICLAV WITH CLINDAMYCIN AND FLUCLOXACILLIN IN AN EXPERIMENTAL RAT MODEL

A rat model of Staphylococcus aureus osteomyelitis was used to compare treatment with co-amoxiclav, flucloxacillin and clindamycin. Co-amoxi clav (amoxyciliin/clavulanic acid 200/50 mg/kg), flucloxacillin (200 m g/kg) and clindamycin (50 mg/kg) were injected subcutaneously tds for 28 days, commencing 14 days after infection. Eight days after cessatio n of treatment, high numbers of staphylococci were recovered from the infected tibiae of all control rats. All treatments, at clinically ach ievable concentrations, significantly (P < 0.05) reduced the bone bact erial titres. However, 50% of tibiae from co-amoxiclav-treated animals were sterile, compared with 17% and 25% from flucloxacillin- or clind amycin-treated animals respectively. Histopathological examination of tibiae reflected the bacteriological results, and showed that the seve rity of the osteomyelitis was greatly reduced in antibiotic-treated an imals compared with non-treated controls. Twenty-eight days after cess ation of therapy, bacterial counts from co-amoxiclav and clindamycin-t reated animals remained significantly (P < 0.05) lower than those of n on-treated controls, although the gross and microscopic appearance of clindamycin and flucloxacillin-treated tibiae suggested that recrudesc ence of the infection may have occurred. The results of this study dem onstrated that co-amoxiclav was as effective as flucloxacillin and cli ndamycin in the treatment of an experimental chronic staphylococcal os teomyelitis.