FIG. 2.

Antimicrobial stability. Quinolone-class compounds were added to molten agar at various concentrations, plates were prepared, and the plates were preincubated at 37°C. At the indicated times, the drug-containing plates were used to determine the MIC₉₉ by applying strain DM4100 (10⁴ CFU), followed by an additional overnight incubation (strain KD1397 was used for the dione UING5-207). Symbols: filled circles, nalidixic acid; filled squares, compound D (PD161144); filled triangles, compound F (PD161148); filled diamonds, compound K (PD160788), multiplication signs, compound I (PD160793); open triangles, UING5-207; and open circles, UING5-249. Similar results were obtained in two replicate experiments.