Antibacterial activity of sparfloxacin against experimental renal infections in mice.
In a murine model of renal infection (Staphylococcus aureus and Escherichia coli), sparfloxacin was compared with ciprofloxacin and fleroxacin. After intrarenal inoculation, mice were treated orally for 5 days. The drugs were administered at five different dosages, ranging from 3.125 to 50 mg/kg of body weight per day for S. aureus and from 0.78 to 12.5 mg/kg/day for E. coli. Evaluation of efficacy was based on the proportional reduction of bacterial counts in the kidney tissues of treated animals compared with those of untreated control animals. For S. aureus, the doses required to clear the infection in 50% of mice were as follows: sparfloxacin, 10 mg/kg/day; ciprofloxacin, 33 mg/kg/day; and fleroxacin, 16 mg/kg/day. For E. coli renal infection, the corresponding dosages were as follows: sparfloxacin, 1.5 mg/kg/day; ciprofloxacin, 2.45 mg/kg/day; and fleroxacin, 1.8 mg/kg/day. Sparfloxacin and fleroxacin have a lower effective dose than ciprofloxacin in these models, probably because ciprofloxacin has a shorter serum half-life than the other two compounds.