Table 2.

Inhibitory effects of quinolones against type II topoisomerases

CompoundIC50 ± SD (MIC) fora:Selectivity
GyrTopo IVTopo IITopo II/GyrTopo II/Topo IV
Sitafloxacin0.13 ± 0.01 (0.008)0.39 ± 0.15 (0.008)2,369 ± 10118,2216,022
DU-68560.18 ± 0.02 (0.016)0.86 ± 0.22 (0.016)1,854 ± 2010,2982,164
DU-68570.42 ± 0.01 (0.031)1.44 ± 0.07 (0.063)1,939 ± 1474,6161,346
DU-68580.69 ± 0.10 (0.063)1.21 ± 0.06 (0.063)1,147 ± 801,663951
Levofloxacin0.39 ± 0.00 (0.031)2.36 ± 0.41 (0.25)1,854 ± 354,754786
Ofloxacin0.71 ± 0.07 (0.063)4.17 ± 1.25 (0.5)2,221 ± 483,129532
Ciprofloxacin0.32 ± 0.02 (0.008)2.83 ± 1.14 (0.25)325 ± 441,016115
  • a IC50s and MICs are expressed as micrograms per milliliter. Gyr, DNA gyrase from E. coli KL-16; Topo IV, topoisomerase IV fromS. aureus FDA 209-P; Topo II, topoisomerase II from human placenta.