The ‘I’ (intermediate susceptibility) in a EUCAST-guided antibiogram never meant impending resistance to your antibiotic. It was never meant to make you find the one ‘S’ (invariably a carbapenem) and use it instead—even if many clinicians did. 

In this episode of Communicable, hosts Marc Bonten and Angela Huttner welcome Profs. Christian Giske (outgoing chair) and Sören Gatermann (newly elected chair) of the European Committee on Antimicrobial Susceptibility Testing (EUCAST) to discuss its recent updates, including the new ‘susceptible dose dependent’ (SDD) label, and to shed light on common misconceptions around the way it sets breakpoints. Breakpoints for Pseudomonas aeruginosa are discussed, as are intravenous fosfomycin’s ‘disappearance’ from the breakpoints table and EUCAST’s new guidance on it. Episode peer-reviewed by Dr. Suzanne van Asten of Radboud University Medical Center.

Literature:
The European Committee on Antimicrobial Susceptibility Testing (EUCAST): https://www.eucast.org/

EUCAST guidance on use of fosfomycin i.v. breakpoints:
https://www.eucast.org/fileadmin/src/media/PDFs/EUCAST_files/Guidance_documents/Use_of_fosfomycin_iv_breakpoints_General_advice_20240528.pdf

In vitro synergy between fosfomycin and ceftazidime/avibactam:
Kroemer, Martens, Decousser et al. Evaluation of in vitro pharmacodynamic drug interactions of ceftazidime/avibactam and fosfomycin in Escherichia coli. J Antimicrob Chemother. 2023 Oct 3;78(10):2524-2534. doi: 10.1093/jac/dkad264