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 ≤0.5 μg/ml, while sparfloxacin, levofloxacin, and ciprofloxacin were bactericidal at concentrations of ≤1.0, ≤2.0, and ≤8.0 μg/ml, respectively. Amoxicillin-clavulanate and clarithromycin were bactericidal at 2× the MIC after 24 h against 12 of 12 strains and against all 8 macrolide-susceptible strains, respectively.