Gopalakrishnan Saranya, Mall Diksha, Pushpavanam Subramaniam, Karmakar Richa
Department of Chemical Engineering, Indian Institute of Technology Madras, Chennai, 600036, India.
Department of Biotechnology, Indian Institute of Technology Madras, Chennai, 600036, India.
Sci Rep. 2025 Feb 11;15(1):5133. doi: 10.1038/s41598-024-84286-3.
The development of rapid, sensitive, and affordable antimicrobial susceptibility testing (AST) is essential for controlling antibiotic overuse, thereby creating a critical checkpoint for the emerging antimicrobial resistance threat. Here, we introduce a novel method of electrochemical monitoring of bacterial growth in a diluted low-conductivity nutrient medium for rapid susceptibility testing using impedance spectroscopy. The method works on the change in charge transfer resistance exhibited by bacteria in response to antibiotics. The proposed Electrochemical Microfluidic device (ε-µD) employs low-cost carbon screen-printed electrodes and uses a simple microfluidic geometry. We explored the utilisation of a diluted nutrient medium as an electrolyte since it provides a higher charge transfer baseline signal for better sensitivity and supports the growth of the bacteria required for detection. The method enables sensitive detection of bacteria even at a low density of 84/mm in three hours of incubation time. For proof of concept, bacteria such as Escherichia coli and Bacillus subtilis were used, and the efficacy of the ampicillin and tetracycline drugs were tested. The experiments were done with the spiked urine samples, which correlated well with the controlled sample. The proposed system enhances the accessibility and affordability of rapid susceptibility testing, enabling its widespread use.
开发快速、灵敏且经济实惠的抗菌药敏试验（AST）对于控制抗生素的过度使用至关重要，从而为新出现的抗菌药物耐药性威胁创建一个关键的检查点。在此，我们介绍一种新型方法，通过阻抗谱在稀释的低电导率营养培养基中对细菌生长进行电化学监测，以进行快速药敏试验。该方法基于细菌对抗生素反应时所表现出的电荷转移电阻变化。所提出的电化学微流控装置（ε-µD）采用低成本的碳丝网印刷电极，并使用简单的微流控几何结构。我们探索了使用稀释的营养培养基作为电解质，因为它能提供更高的电荷转移基线信号以获得更好的灵敏度，并支持检测所需细菌的生长。该方法能够在三小时的孵育时间内，即使在细菌低密度为84/mm时也能灵敏地检测到细菌。为了验证概念，使用了诸如大肠杆菌和枯草芽孢杆菌等细菌，并测试了氨苄青霉素和四环素药物的疗效。实验使用了加标的尿液样本，其与对照样本相关性良好。所提出的系统提高了快速药敏试验的可及性和经济性，使其能够广泛应用。
