Expected phenotypes and expert rules are important complements to antimicrobial susceptibility testing

Abstract

The first European Committee on Antimicrobial Susceptibility Testing (EUCAST) expert rules document was published in 2008; this was followed in 2013, 2016, and 2020 by subsequent versions [1–4]. Changes in taxonomy, the widespread availability and use of matrix-assisted laser desorption-ionization time of flight mass spectrometry (MALDI-TOF) for bacterial identification, the development of new antimicrobials, and changes in the definitions in the clinical interpretive categories (sensitive (S), susceptible increased exposure (I), resistant (R)) of susceptibility testing results have prompted a revision of the intrinsic resistance tables and expert rules.