Figure 2.

Fitness and drug resistance

(A) We measured relative fitness (the ratio between fitness in each drug concentration versus the no-drug condition [control]) in a time course experiment at several concentrations of flz and ani. Fitness was measured as the area under the time-versus-optical density (OD) curve (fAUC). The graph depicts an illustrative example of two independently evolved replicates of the CST109 strain in the ANI and YPD evolution experiments. The shaded areas represent the median absolute deviation across technical replicates. As a proxy for drug resistance, we defined rAUC as the AUC of these data (normalized by the maximum AUC, in which fitness is maintained across all the range of concentrations [AUC_MAX]).50% of growth inhibition, as compared to the no-drug control, is marked as MIC₅₀.

(B) rAUC for flz (top) and ani (bottom) across all samples in our experiments. Each point corresponds to an independently evolved biological replicate. Note that some samples have an rAUC above 1.0, where fitness did not drop upon increasing drug concentration (suggesting high resistance). In addition, Figure S6 includes information about the drug resistance levels among samples with different mutations.

(C) The relationship between ani and flz resistance across all samples. Dashed lines indicate median rAUCs levels for each drug in the YPD samples and rAUC_MAX (1.0). Each point corresponds to a biological replicate, and the error bars reflect the median absolute deviation across technical replicates. Each marker corresponds to a different strain.

(D) Fitness in the absence of drug (measured as the log₂ fold change in fAUC (see [A] between each sample and the median fAUC in the WT of the matching strain). Note that Figure S6 includes information about relative fitness levels among samples with different mutations.

(E) Fitness in the absence of drugs is slightly correlated with the levels of flz, but not ani, resistance (rAUC). Spearman’s correlation coefficient (r) and p value are shown for flz (left) and ani (right) resistance. The correlation for flz resistance was maintained when considering only samples with mild fitness defects (fitness >−1, r = −0.22, p = 0.0029). Only resistant samples, defined as those with a log₂ fold increase above 1 as compared to the WT (Figure S1D), were included in this analysis. The individual fitness and susceptibility measurements for each sample can be found in Data S1.