Antibiotic susceptibility testing (AST) is a routine procedure in diagnostic laboratories to determine pathogen resistance profiles toward antibiotics. The need for fast and accurate resistance results is rapidly increasing with a global rise in pathogen antibiotic resistance over the past years. Microfluidic technologies can enable AST with lower volumes, lower cell numbers, and a reduction in the sample-to-result time compared to state-of-the-art systems. We present a protocol to perform AST on a miniaturized nanoliter chamber array platform. The chambers are filled with antibiotic compounds and oxygen-sensing nanoprobes that serve as a viability indicator. The growth of bacterial cells in the presence of different concentrations of antibiotics is monitored; living cells consume oxygen, which can be observed as an increase of a luminesce signal within the growth chambers. Here, we demonstrate the technique using a quality control Escherichia coli strain, ATCC 35218. The AST requires 20 μL of a diluted bacterial suspension (OD600 = 0.02) and provides resistance profiles about 2-3 h after the inoculation. The microfluidic method can be adapted to other aerobic pathogens and is of particular interest for slow-growing strains.
Keywords: Antibiotic susceptibility testing; Microfluidics; Thermoplastic microfluidic devices.
© 2024. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.