Figure 4.

Cross-resistance and collateral sensitivity phenotypes of the gradient, 25 and 50% increment evolved strains. Fold increase (blue) or decrease (red) of the IC₈₅ compared to the wild type (WT) is indicated for each individual strain. The collateral sensitivity as well as cross-resistance is similar across experimental setups. Collateral sensitivity toward tetracycline (TET) of strains adapted to amikacin (AMK) under the 25% increment approach is elevated (P < 0.05) compared to strains evolved to the drug gradient. The cross-resistance of strains evolved to piperacillin (PIP) tested against TET is increased (P < 0.05) in the 25% increment adapted strains compared to the gradient evolved strains.