A comprehensive report on the 1st Swiss-EUCAST Antimicrobial Susceptibility Testing (AST) Meeting.

Antimicrobial susceptibility testing (AST) is being reshaped by increasingly complex resistance mechanisms, revised interpretive frameworks, and rapid phenotypic and genomic technologies. The first Swiss-EUCAST AST Meeting, held in Zurich on 4 May 2026, brought together more than 100 clinical microbiologists, researchers, and infectious diseases specialists to discuss how these developments should be translated into routine diagnostics. The meeting focused on three topics: the limitations of genotype-phenotype prediction, the ongoing need for standardized interpretation within the European Committee on Antimicrobial Susceptibility Testing (EUCAST), and the potential of new technologies to reduce turnaround times. Discussions specifically on Pseudomonas aeruginosa, as well as on pathogens without clinical breakpoints, carbapenemase-producing Enterobacterales, expected phenotypes, epidemiological cutoff values, rapid phenotypic susceptibility tests, and whole-genome sequencing, showed that no single method can eliminate all diagnostic uncertainties. In summary, it was concluded that standardized phenotypic ASTs will continue to serve as a clinical reference in the future, but molecular and genomic methods offer additional advantages in terms of speed, as well as insights into mechanisms of action and epidemiological relations.