Application of under-oil open microfluidic systems for rapid phenotypic antimicrobial susceptibility testing

Antimicrobial susceptibility testing (AST) remains the cornerstone of effective antimicrobial selection and optimization in patients. Despite recent advances in rapid pathogen identification and resistance marker detection with molecular diagnostics, phenotypic AST methods remain relatively unchanged over the last few decades. Guided by the principles of microfluidics, we describe the application of a multi-liquid-phase microfluidic system, named under-oil open microfluidic systems (UOMS) to achieve a rapid phenotypic AST. UOMS provides a next-generation solution for AST (UOMS-AST) by implementing and recording a pathogen antimicrobial activity in micro-volume testing units under an oil overlay with label-free, single-cell resolution optical access. UOMS-AST can accurately and rapidly determine antimicrobial activity from nominal sample/bacterial cells in a system aligned with clinical laboratory standards. Further, we combine UOMS-AST with cloud lab data analytic techniques for real-time image analysis and report generation to provide a rapid (i.e., <4 h) sample-to-answer turnaround time, shedding light on its utility as a next-generation phenotypic AST platform for clinical application.