On‐chip spectroscopic assessment of microbial susceptibility to antibiotics within 3.5 hours

• Published in: Journal of biophotonics Vol. 10; no. 11; pp. 1547 - 1557
• Main Authors: Schröder, Ulrich‐Christian, Kirchhoff, Johanna, Hübner, Uwe, Mayer, Günter, Glaser, Uwe, Henkel, Thomas, Pfister, Wolfgang, Fritzsche, Wolfgang, Popp, Jürgen, Neugebauer, Ute
• Format: Journal Article
• Language: English
• Published: Germany 01.11.2017
• Subjects: Anti-Bacterial Agents - pharmacology; antibiotic resistance; antibiotic susceptibility testing; device-independent classification; dielectrophoresis (DEP); E. coli, ciprofloxacin; Escherichia coli - drug effects; Lab-On-A-Chip Devices; microfluidic; Raman spectroscopy; Spectrum Analysis, Raman - instrumentation; Time Factors; antibiotic resistance; dielectrophoresis (DEP); device-independent classification; Raman spectroscopy; microfluidic; antibiotic susceptibility testing; E. coli, ciprofloxacin
• ISSN: 1864-063X; 1864-0648
• DOI: 10.1002/jbio.201600316

In times of rising antibiotic resistances, there is a high need for fast, sensitive and specific methods to determine antibiotic susceptibilities of bacterial pathogens. Here, we present an integrated microfluidic device in which bacteria from diluted suspensions are captured in well‐defined regions using on‐chip dielectrophoresis and further analyzed in a label‐free and non‐destructive manner using Raman spectroscopy. Minimal sample preparation and automated sample processing ensure safe handling of infectious material with minimal hands‐on time for the operator. Clinical applicability of the presented device is demonstrated by antibiotic susceptibility testing of Escherichia coli towards the commonly prescribed second generation fluoroquinolone ciprofloxacin. Ciprofloxacin resistant E. coli were differentiated from sensitive E. coli with high accuracy within roughly three hours total analysis time paving the way for future point‐of‐care devices. Spectral changes leading to the discrimination between sensitive and resistant bacteria are in excellent agreement with expected metabolic changes in the bacteria due to the mode of action of the drug. The robustness of the method was confirmed with experiments involving different chip devices with different designs, both electrode as well as microfluidics design, and material. Furthermore, general applicability was demonstrated with different operators over an extended time period of half a year. In times of rising antibiotic resistances, there is a high need for fast, sensitive and specific methods to determine antibiotic susceptibilities of bacterial pathogens. Here, an integrated microfluidic device is presented in which bacteria from diluted suspensions are captured in well‐defined regions using on‐chip dielectrophoresis and are further analyzed using Raman spectroscopy. Minimal sample preparation and automated sample processing ensure safe handling of infectious material with minimal hands‐on time for the operator. The robustness of the method was confirmed with experiments involving different chip devices with different designs, both electrode as well as microfluidics design, and material.