Example of SGT method use: assessment of the relative efficacy of compounds on the size of the persister cell fraction using the SGT method. (A) PA14 cells were grown to the mid-logarithmic stage (arrow) in the absence or presence of AA (0.75 mM), 3-AA (0.75 mM), gentamicin (Gent, 1.5 mg/L) and ciprofloxacin (Cipro, 0.04 mg/L). Meropenem was applied as in Figure 2. (B) A comparison of survival fraction sizes obtained by SGT (empty bars) and CFU counting (filled bars) methods, presented as log2 fold change. SGT values were determined using a threshold OD600nm = 0.15. ∆SGT values were calculated as the difference between the SGT values of meropenem treated and untreated cultures and ∆∆SGT values as the difference between compound-treated cultures and the untreated calibrator. The SGT and CFU count data were not significantly different (p > 0.05).