Paper-Based Semi-quantitative Antimicrobial Susceptibility Testing

Antimicrobial resistance is increasingly recognized as a major threat to global health. To combat this emerging threat, accessible antimicrobial susceptibility testing should be prioritized as a key component of stewardship efforts. In this work, we developed a user-friendly paper-based test that provides visual readout of bacterial antibiotic susceptibility in a semiquantitative format. We leveraged on-chip paper microfluidics to enable multiplexed testing of multiple antibiotic dilutions with a single sample addition step, replicating the functionality of traditional broth-dilution-based susceptibility testing in a simplified format. Our paper-based test offers several advantages including low sample volume requirement and lack of need for humidity control during incubation, an innovation that addresses a key limitation of conventional paper-microfluidic devices. Using several clinically relevant bacterial organisms and antimicrobial agents, we demonstrate that our colorimetric readout approach provides a strong predictor of susceptibility category.