Antibiotic Susceptibility Testing (AST)

A sufficiently fast and simple antimicrobial susceptibility testing (AST) is urgently required to guide effective antibiotic usages and to surveil the antimicrobial resistance rate. Here, we establish a rapid, quantitative, and high-throughput phenotypic AST by measuring electrons transferred from the interiors of microbial cells to external electrodes. Because the transferred electrons are based on microbial metabolic activities and are inversely proportional to the concentration of potential antibiotics, the changes in electrical outputs can be readily used as a transducing signal to efficiently monitor bacterial growth and antibiotic susceptibility. The sensing is performed by directly measuring the total energy, or all the accumulated microbial electricity, generated by microbial fuel cells (MFCs) arranged in a large-capacity disposable, paper-based testbed. Our new approach provides quantitative, actionable minimum inhibitory concentration (MIC) results within just a couple of hours because it measures electricity produced by bacterial metabolism instead of the days needed for growth-observation methods. Moreover, as the equipment needed is simple, common, and inexpensive, our test has immense potential to be adopted in the field or resource-limited hospitals and labs to provide insightful assessments for research and clinical practices.