Overnight cultures of 384 strains in the Keio collection (example plate shown in Fig. 2a) were seeded onto nitrocellulose membranes in 384-density in biologically independent duplicate experiments, and the membranes were placed onto LB media and incubated to stationary phase for 24 h. Nitrocellulose membranes containing mature colonies were then transferred to LB media supplemented with ciprofloxacin and incubated for the duration noted. Ciprofloxacin-treated colonies were then transferred to LB media supplemented with 50 µg/ml TTC for 1 h to stain live colonies. Fluorescence values of colonies treated with ciprofloxacin for varying durations were averaged and normalized to the non-drug-treated control (t = 0). Darker green represents greater fluorescence. These data show that increasing the duration of exposure to ciprofloxacin enhanced colony killing of sensitive strains. 24 h of ciprofloxacin exposure was selected to sufficiently increase the fluorescence of sensitive strains relative to that of non-sensitive strains.