Figure 3.

Bactericidal effects of quinolones on E. coli. Exponentially growing cultures of wild-type E. coli (A, strain DM4100), a gyrA mutant (B, strain GP201), or a gyrA parC mutant (C, strain KD1366) were incubated with the indicated concentrations of PD161148 (C8-OMe, ○) and PD160793 (C8-H, •) for 2 hr. Aliquots were then removed, diluted, and plated on drug-free agar for determination of viable cells. Similar results were obtained in two replicate experiments and with another pair of compounds, PD135042 and ciprofloxacin.