FIG. 5.

Lethal activity of fluoroquinolone dimers in the presence and absence of chloramphenicol. Exponentially growing cultures of wild-type M. smegmatis were incubated with increasing concentrations of dimer fluoroquinolones. Names of compounds tested are indicated in each panel. Cells were treated for 18 h in the presence (filled circles) or absence (open circles) of chloramphenicol, which was added 1 h prior to fluoroquinolone treatment. Aliquots were then removed, diluted, and plated on drug-free 7H10 agar for determination of viable cells. A replicate experiment produced similar results.