Rapid Antimicrobial Susceptibility Testing (AST): Overview of New Commercially Available Automated Phenotypic Tools for Minimum Inhibitory Concentration (MIC) Determination

Antimicrobial resistance (AMR) represents one of the most urgent global health threats, significantly impacting patient outcomes, healthcare systems, and economic sustainability. Rapid and accurate antimicrobial susceptibility testing (AST) are essential to guide targeted therapy, reduce inappropriate antimicrobial use, and support antimicrobial stewardship programs. However, conventional phenotypic AST methods, including broth microdilution, disk diffusion, agar dilution, and gradient strip tests, remain labor-intensive and require prolonged turnaround times, often delaying optimal therapeutic decisions. Although automated commercial platforms such as VITEK 2, BD Phoenix, MicroScan WalkAway, and Sensititre ARIS have improved laboratory workflow and standardization, they still rely on culture-based approaches and typically require 16–36 h to generate minimum inhibitory concentration (MIC) results. In recent years, several innovative rapid phenotypic AST technologies have emerged, aiming to significantly shorten the time to susceptibility results while maintaining high accuracy. This review provides an overview of currently available rapid automated phenotypic platforms for MIC determination, including VITEK® Reveal™, ASTar, FASTinov®AST, QuickMIC®, and the Accelerate Pheno® system. These systems employ advanced technologies such as volatile organic compound detection, flow cytometry, microfluidics, real-time imaging, and morphokinetic cellular analysis to deliver susceptibility results within a few hours directly from positive blood cultures. We summarize their technical principles, antibiotics and pathogens included, performances, and current limitations. Overall, the implementation of rapid phenotypic AST tools has the potential to substantially improve clinical decisions, optimize antimicrobial therapy, and contribute to fight AMR.