FIGURE 3.

The epidemiological cut-off (ECOFF) of amoxicillin for Escherichia coli; ECOFF is the MIC (8 μg/mL) that best separates the two sub-populations of the observed MICs (from 0.25 to 256 μg/mL) distribution, i.e., the wild-type population and of the non-wild-type population. ECOFF is a parameter that can be determined using simple visual inspection in the case of a clear bimodal distribution (as here) or by statistical techniques when greater certainty of the estimation is required (EUCAST raw data).