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Antibacterial activity of sparfloxacin against experimental renal infections in mice
A Georgopoulos1, S M Feistauer, W Graninger
1Clinical Department for Infectious Diseases and Chemotherapy, University Clinic for Internal Medicine I, Vienna, Austria.
Abstract:
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.
Insights
Sparfloxacin and fleroxacin demonstrate superior efficacy in treating murine kidney infections caused by Staphylococcus aureus and Escherichia coli compared to ciprofloxacin. These fluoroquinolones require lower dosages for bacterial clearance, suggesting improved pharmacokinetic profiles.
Area of Science:
- Pharmacology
- Infectious Diseases
- Microbiology
Background:
- Renal infections pose significant therapeutic challenges.
- Fluoroquinolones are a critical class of antibiotics for treating bacterial infections.
- Comparative efficacy studies are essential for optimizing antimicrobial therapy.
Purpose of the Study:
- To compare the in vivo efficacy of sparfloxacin, ciprofloxacin, and fleroxacin against Staphylococcus aureus and Escherichia coli renal infections in a murine model.
- To determine the minimum effective dosages of these fluoroquinolones required for bacterial clearance in kidney tissues.
Main Methods:
- A murine model of intrarenal inoculation with Staphylococcus aureus and Escherichia coli was established.
- Mice were orally administered sparfloxacin, ciprofloxacin, or fleroxacin at varying dosages for five consecutive days.
- Efficacy was assessed by quantifying the proportional reduction in bacterial counts in kidney tissues compared to untreated controls.
Main Results:
- Sparfloxacin and fleroxacin exhibited lower effective doses than ciprofloxacin for both S. aureus and E. coli renal infections.
- For S. aureus, the 50% effective doses were: sparfloxacin (10 mg/kg/day), fleroxacin (16 mg/kg/day), and ciprofloxacin (33 mg/kg/day).
- For E. coli, the 50% effective doses were: sparfloxacin (1.5 mg/kg/day), fleroxacin (1.8 mg/kg/day), and ciprofloxacin (2.45 mg/kg/day).
Conclusions:
- Sparfloxacin and fleroxacin are more potent than ciprofloxacin in treating experimental renal infections caused by S. aureus and E. coli.
- The superior efficacy of sparfloxacin and fleroxacin may be attributed to their longer serum half-lives compared to ciprofloxacin.
- These findings support the potential clinical utility of sparfloxacin and fleroxacin for renal infections.