19 Mar 2021

EUCAST breakpoints offer two levels of susceptible (S and I).

In 2019, EUCAST abandoned the previously used definitions of S, I and R, and introduced categories S (Susceptible, standard dose), I (Susceptible, increased exposure) and R (Resistant). All breakpoints, dosages and modes of administration were reviewed and revised to match the changed definitions. The new system has two levels of "susceptible" whereas the previous system in effect offered two levels of resistance. Microbiological laboratories were expected to implement the new definitions by the end of 2020. To do so is paramount for any lab on EUCAST breakpoints since all breakpoints in breakpoint table v 11.0 have been reviewed to fit the new definitions. For more information, see the EUCAST webpage explaining the changed definitions.