Rapid EUCAST disc diffusion testing of MDR<i>Escherichia coli</i>and<i>Klebsiella pneumoniae</i>: inhibition zones for extended-spectrum cephalosporins can be reliably read after 6 h of incubation

Abstract

Inhibition zone reading at 6 h is an accurate method for susceptibility testing of extended-spectrum cephalosporins for Enterobacteriaceae. For other antimicrobials, 6 h reading can be used for preliminary reports of clearly resistant or susceptible isolates, preferably with application of adjusted breakpoints including an area of uncertainty between susceptible and resistant values.