Antipneumococcal activity of grepafloxacin compared to that of other agents by time-kill methodology

Time-kill studies compared the activities of grepafloxacin with those of ciprofloxacin, levofloxacin, sparfloxacin, amoxicillin-clavulanate, and clarithromycin against 12 pneumococcal strains. Grepafloxacin was bactericidal after 24 h against all strains at a concentration of < or = 0.5 microg/ml, while sparfloxacin, levofloxacin, and ciprofloxacin were bactericidal at concentrations of < or = 1.0, < or = 2.0, and < or = 8.0 microg/ml, respectively. Amoxicillin-clavulanate and clarithromycin were bactericidal at 2x the MIC after 24 h against 12 of 12 strains and against all 8 macrolide-susceptible strains, respectively.