To overcome the widespread misuse of antibiotics and reduce the growing problem of multidrug resistance, rapid, sensitive and specific novel methods to determine bacterial antibiotic susceptibility are needed. This study presents a combined dielectrophoresis (DEP) - Raman Spectroscopy (RS) method to obtain direct, real-time measurements of the susceptibility of a suspension of planktonic bacteria without labelling or other time-consuming and intrusive sample preparation processes. Using an in-house constructed DEP-Raman device, we demonstrated the susceptibility of Escherichia coli MG1655 towards the second-generation fluoroquinolone antibiotic ciprofloxacin (CP) after only 1 h of treatment, by monitoring spectral changes in the chemical fingerprint of bacteria related to the mode of action of the drug. Spectral variance was modelled by multivariate techniques and a classification model was calculated to determine bacterial viability in the exponential growth phase at the minimum bactericidal concentration (MBC) over a 3 h time span. Further tests at a sub-minimum inhibitory concentration (MIC) and with a CP-resistant E. coli were carried out to validate the model. The method was then successfully applied for class prediction in a biocide cross-induced tolerance assay that involved pre-treating E. coli with triclosan (TCS), an antimicrobial used in many consumer products. High specificity and adequate sensitivity of the proposed method was thereby demonstrated. Simultaneously, standard microbiological assays based on cell viability, turbidity and fluorescence microscopy, were carried out as reference methods to confirm the observed Raman response.

为了克服抗生素的广泛滥用并减少日益增长的多药耐药性问题，需要快速，灵敏和特异的新方法来确定细菌对抗生素的敏感性。这项研究提出了一种组合的介电电泳（DEP）-拉曼光谱（RS）方法，可直接实时测量浮游细菌悬浮液的磁化率，而无需进行标记或其他费时且费力的样品制备过程。使用内部构建的DEP-Raman设备，我们证明了大肠杆菌的敏感性通过监测与药物作用方式有关的细菌化学指纹图谱的变化，MG1655在第二代氟喹诺酮类抗生素环丙沙星（CP）治疗后仅用了1小时。通过多元技术对光谱方差建模，并计算分类模型，以确定在3小时时间内最小杀菌浓度（MBC）下指数生长期的细菌生存力。在最小抑菌浓度（MIC）以及具有CP抵抗力的大肠杆菌下进行了进一步测试，以验证模型。然后，该方法成功地应用于涉及预处理大肠杆菌的杀生物剂交叉诱导的耐受性测定中的类别预测三氯生（TCS），一种用于许多消费品的抗菌剂。从而证明了所提出方法的高特异性和足够的敏感性。同时，基于细胞生存力，浊度和荧光显微镜的标准微生物检测方法被用作参考方法，以确认观察到的拉曼反应。