Figure 3.

Phenotypic changes in drug resistance and growth rate after the adaptive laboratory evolution experiment. (A) The fold-increase of the IC₈₅ compared to the wild type (WT) is displayed for each drug. The evolved resistance levels are not significantly different for amikacin (AMK) and piperacillin (PIP) across different experimental setups, which are referred to as G for the gradient approach, 25 for the 25% increment and 50 for the 50% increment method. However, strains adapted to tetracycline (TET) display significant changes in drug resistance. The clinical breakpoint normalized to fold-increase to the media adapted wild type (WT) of each drug is marked with a light gray panel. (B) The doubling time relative to the wild type is shown for the same isolated colony used for the IC₈₅ determination as well as for six additional colonies, colored in gray. A significantly lower doubling time for the 25% increment lineages compared to the gradient evolved lineages can be observed for all drugs. ^*P < 0.05, ^**P < 0.01, ^***P < 0.001, ^****P < 0.0001.