Comparative antistreptococcal activity of two newer fluoroquinolones, levofloxacin and sparfloxacin

The objective of this study uas to evaluate the in vitro activity of sparfloxacin, levofloxacin, ofloxacin, and ciprofloxacin against contemporary strains of streptococci. Susceptibility testing of a panel of 300 recent clinical isolates of streptococci (100 each of beta-hemolytic, viridans group, and Streptococcus pneumoniae) using reference broth microdilution methods was performed, and the results were compared. Sparfloxacin was the most active of the four tested fluoroquinolones, inhibiting 99-100% of all isolates at concentrations of less than or equal to 1 mu g/ml, and was two-to eightfold move potent than the three comparative agents. Levofloxacin was also quite active, inhibiting 98-100% of the isolates af concentrations less than or equal to 2 mu g/ml. Both sparfloxacin and levofloxacin possess an improved spectrum and potency against contemporary strains of streptococci compared to currently available fluoroquinolones. (C) 1997 Elsevier Science Inc.