Table 2.

Fluoroquinolone susceptibilities of S. pneumoniae C3LN4, first-step mutants, and clinical isolates

StrainFluoroquinolone MIC (μg/ml)a
LVFXOFLXCPFXSPFXSTFX
C3LN40.10.30.20.150.005
SPFX1b 0.10.30.2 0.4 0.005
CPFX1c 0.10.3 0.5 0.150.005
OFLX1d 0.3 0.75 0.6 0.8 0.005
JP17e 6.25 12.5 6.25 1.56 0.39
JP27e 25 50 50 25 0.39
  • a LVFX, levofloxacin; OFLX, ofloxacin; CPFX, ciprofloxacin; SPFX, sparfloxacin; STFX, sitafloxacin. Those MICs greater than those for the wild type are shown in boldface type.

  • b Selected with sparfloxacin (the MICs for the other five mutants were identical).

  • c Selected with ciprofloxacin (MICs for the other 11 mutants were identical).

  • d Selected with ofloxacin.

  • e Clinical isolates.