Antimicrobial susceptibility testing (AST) is a diagnostic tool used in clinics to identify the microbial species causing an infection and determine their susceptibility to various drugs and concentrations. Current AST protocols require at least 2–3 days to complete. Owing to the urgency of blood infections, such delays can lead to inaccurate and often ineffective antimicrobial prescriptions, severely impacting survival rates. In this study, Kim, Kang, Jang et al. report a phenotype-based, ultra-rapid and blood culture-free AST (uRAST) approach and evaluate its clinical applicability.

Next, to identify the microbial species causing the infection, the authors developed a quick-mapping identification assay consisting of a library of silica-coated microdiscs immobilized with single-stranded DNA probes that can hybridize to genomic sequences of the corresponding pathogen. Unique hole patterns assigned to each gene were used to differentiate bacterial identities, facilitating a highly multiplexed, one-pot assay.