Table 3.

Fluoroquinolone susceptibilities of purified type II topoisomerases

StrainFluoroquinoloneIC50(μg/ml)B/A ratio
Topoisomerase IV (A)DNA gyrase (B)
C3LN4Levofloxacin6549.0
Ciprofloxacin79613.7
Sparfloxacin711416.3
Ofloxacin10888.8
Sitafloxacin221.0
SPFX1a Levofloxacin6549.0
Ciprofloxacin79613.7
Sparfloxacin 21 b 1145.4
Ofloxacin10888.8
Sitafloxacin221.0
CPFX1c Levofloxacin6549.0
Ciprofloxacin 22 964.4
Sparfloxacin711416.3
Ofloxacin10888.8
Sitafloxacin221.0
OFLX1Levofloxacin 13 544.2
Ciprofloxacin 25 963.8
Sparfloxacin 38 1143.0
Ofloxacin 25 883.5
Sitafloxacin221.0
JP17Levofloxacin>200>200
Ciprofloxacin>200>200
Sparfloxacin>200>200
Ofloxacin>200>200
Sitafloxacin840.5
JP27Levofloxacin>200>200
Ciprofloxacin>200>200
Sparfloxacin>200>200
Ofloxacin>200>200
Sitafloxacin1060.6
  • a Identical results were obtained with CPFX2.

  • b Values in boldface type indicate an increase in IC50 over that found for the wild type.

  • c Identical results were obtained with SPFX2.