Validation of EUCAST rapid antimicrobial susceptibility testing directly from positive blood cultures in a non-automated lab setting.

Introduction: To speed up antimicrobial susceptibility testing (AST), the European Committee on Antimicrobial Susceptibility Testing (EUCAST) proposed rapid AST (RAST), a disk diffusion method to be read after 4, 6 and 8 hours of incubation. We investigated the feasibility of implementation of RAST in a non-automated lab setting.

Materials & Methods: To this end, reference strains as well as a variety of clinical and resistant strains were used to spike sterile hemocultures (BioMérieux BACT/ALERT 3D® and Becton Dickinson BACTEC FX® systems), followed by RAST in comparison to classical long-incubation AST.

EUCAST rapid antimicrobial susceptibility testing (RAST) compared to conventional susceptibility testing: implementation and potential added value in a tertiary hospital in Belgium.

Objectives: EUCAST breakpoints for short incubation disk diffusion allow rapid antimicrobial susceptibility testing (RAST) directly from positive blood cultures. We evaluate the RAST methodology and assess its potential added value in a setting of low prevalence of multidrug-resistant (MDR) organisms.

Methods: In our two-part study, we performed RAST on 127 clinical blood cultures at 6 and 8 h and determined categorical agreement with direct susceptibility testing.