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?

  • $\begingroup$ Wouldn't it be a sensitivity assay like Kirby Bauer? $\endgroup$
    – rhill45
    Nov 17, 2015 at 18:11
  • 1
    $\begingroup$ You could do percent viability of the microbe at MIC50 versus control over a time course. The lower the percent viability, the more sensitive the strain is to the compound. There are other factors you would need to test such as biofilm formation prevention, killing of sessile versus planktonic microbes, but % viability should tell you the sensitivity of the strain to the compound. $\endgroup$
    – AMR
    Dec 18, 2015 at 14:58

1 Answer 1


I think you are after the slope of the dose-response curve:

DR curve
Dose-response curve. Souce: Merck

The slope indicates the change in response per unit dose, which translates to sensitivity.


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