Nguyen Ann V, Azizi Morteza, Yaghoobi Mohammad, Dogan Belgin, Zhang Shiying, Simpson Kenneth W, Abbaspourrad Alireza
Department of Food Science, College of Agricultural and Life Sciences, Cornell University, Stocking Hall, Ithaca, New York 14853, United States.
Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, 602 Tower Rd., Ithaca, New York 14853, United States.
Anal Chem. 2021 Apr 13;93(14):5789-5796. doi: 10.1021/acs.analchem.0c05248. Epub 2021 Mar 31.
Conventional antibiotic susceptibility testing (AST) assays such as broth microdilution and Kirby-Bauer disk diffusion are time-consuming (e.g., 24-72 h) and labor-intensive. Here, we present a microfluidic platform to perform AST assays with a broad range of antibiotic concentrations and controls. A culture medium stream was serially enriched with antibiotics along the length of the platform diffusion and flow-directing mass convection mechanisms, generating a concentration gradient captured in a series of microchamber duplicates. We observed an agreement between the simulated and experimental concentration gradients and applicability to a variety of different molecules by changing the loading time according to a simple linear equation. The AST assay in our platform is based on bacterial metabolism, indicated by resazurin fluorescence. The small reaction volume enabled a minimum inhibitory concentration (MIC) to be determined in 4-5 h. Proof-of-concept functionality testing, using human isolates and clinically important antibiotics from different classes, indicated a high rate of agreement (94%: MIC within ±1 two-fold dilution of the reference method) of on-chip MICs and conventional broth microdilution. Overall, our results showed that this microfluidic platform is capable of determining antibiotic susceptibility in a rapid and reliable manner.
传统的抗生素敏感性测试（AST）方法，如肉汤微量稀释法和 Kirby-Bauer 纸片扩散法，耗时较长（例如24 - 72小时）且 labor-intensive。在此，我们展示了一种微流控平台，可用于在广泛的抗生素浓度和对照条件下进行AST测定。沿着平台的长度方向，通过扩散和流动导向的质量对流机制，培养基流被连续富集抗生素，从而在一系列微腔复制品中产生浓度梯度。通过根据一个简单的线性方程改变加载时间，我们观察到模拟浓度梯度与实验浓度梯度之间的一致性以及对各种不同分子的适用性。我们平台中的AST测定基于刃天青荧光所指示的细菌代谢。小反应体积使得能够在4 - 5小时内确定最低抑菌浓度（MIC）。使用来自不同类别的人类分离株和临床重要抗生素进行的概念验证功能测试表明，芯片上的MIC与传统肉汤微量稀释法的一致性很高（94%：MIC在参考方法的±1倍稀释范围内）。总体而言，我们的结果表明，这种微流控平台能够以快速且可靠的方式确定抗生素敏感性。
