In a dose-response curve the % inhibition can be plotted against concentration antagonist. In our case, the effect of the antagonist is tested in different genetic variants of a microbe.
When trying to determine the potency of a drug on the different variants, I compared the IC50 values. The lower the concentration required for 50% inhibition, the more potent the drug.
When comparing drug efficacy, I compare the concentrations required to reach Emax or the maximum inhibition that each drug can exert - which turns out to be 100% inhibition.
To compare sensitivity, how does one proceed?