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

• Published in: Acta clinica belgica (English ed. Online) 2024-10, p.1-8
• Main Authors: Strubbe, Gregory, Van Honacker, Eveline, Vandendriessche, Stien, Messiaen, Anne-Sophie, Verhasselt, Bruno, Boelens, Jerina
• Format: Article
• Language: English
• ISSN: 1784-3286; 2295-3337; 2295-3337
• DOI: 10.1080/17843286.2024.2421075

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. 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. Our results with reference strains show that reading RAST after 4 hours is frequently too soon to obtain clinical results, and that reference strain did yield readable inhibition zones in RAST when harvested from BioMérieux BACT/ALERT 3D® bottle cultures. In a wider panel of strains, Gram positives RAST results were very similar to standard AST, while with Gram negative species errors were more frequently observed, limiting clinical implementation.