Oral quinolone in the treatment of experimental polymicrobial puerperal infection in rabbits

OBJECTIVE: To evaluate the efficacy of oral levofloxacin in the treatment of experimental polymicrobial puerperal infection in the rabbit. METHODS: Timed pregnant rabbits were anesthetized on day 29 or 30 of a 31-day gestation and 106 colony-forming units each of Escherichia coli, group B streptococcus, and Staphylococcus saccharolyticus were inoculated endoscopically in the cervices. Labor was induced with intramuscular oxytocin 16 hours later if it had not occurred spontaneously. The animals then were observed every 3 hours for fever; when a temperature of 104F was reached, treatment was begun. Animals were assigned randomly in a blinded, placebo-controlled manner to received oral levofloxacin (10 mg/kg/day) or placebo and were treated twice daily for 4-5 days. The animals were killed and necropsy was performed 4-6 hours after the last dose. Specimens for culture were taken from uterine horns, peritoneum, and blood. Levofloxacin concentrations were determined from blood samples at necropsy. Clinical cure of fever, eradication of microbes, and presence of uterine abscesses at necropsy were assessed. RESULTS: Compared with placebo-treated rabbits, levofloxacin-treated animals had a significantly greater number of clinical cures (nine of 11 versus four of 12, P=.027) and significantly more eradication of E coli (ten of 11 versus five of 12, P=.022). Four uterine abscesses were seen in 12 placebo-tested animals, compared with none of 11 levofloxacin-tested animals (P=.093). There was no difference in eradication of group B streptococcus between the two groups. No blood cultures were positive for organisms in any animal. Levofloxacin was detected in all treated animals, but at low levels (less than 1 microg/mL). CONCLUSION: Treatment of experimental puerperal infection with oral levofloxacin in rabbits resulted in significantly more clinical cures and eradication of E coli compared with treatment with placebo.