FIG. 2.
Effect of fluoroquinolone concentration on selection of resistant mutants. M. tuberculosis isolate TN7804 was applied to agar plates containing the indicated concentrations of PD161148 (C-8-methoxy; open circles) or PD160793 (C-8-H; filled circles). After incubation, the number of drug-resistant colonies was recorded and plotted relative to the number of CFU applied to the drug-free agar plates. The arrowhead indicates the drug concentration at which no colony was recovered from plates containing C-8-methoxy fluoroquinolone when more than 1010 cells were applied. (Inset) Data for points where the fraction of cells recovered was below 10−7, replotted using a linear scale.