title: Real-time investigation of antibiotics-induced oxidative stress and superoxide release in bacteria using an electrochemical biosensor.
abstract: The involvement of oxidative stress in the mechanism of antibiotics-meditated cell death is unclear and subject to debate. The kinetic profile and a quantitative relationship between the release of reactive oxygen species (ROS), bacteria and antibiotic type remain elusive. Here we report direct measurements and analytical quantification of the release of superoxide radicals (O2(·-)), a major contributor to ROS, in antibiotics-treated bacterial cultures using a cytochrome c electrochemical biosensor. The specificity of electrochemical measurements was established by the addition of superoxide dismutase (SOD) which decreased the O2(·-) signal. Measurements using a general ROS-specific fluorescence dye and colony forming units (CFU) assays were performed side-by-side to determine the total ROS and establish the relationship between ROS and the degree of lethality. Exposure of Escherichia coli and Listeria monocytogenes cultures to antibiotics increased the release of O2(·-) radicals in a dose-dependent manner, suggesting that the transmembrane generation of ROS may occur as part of the antibiotic action. The study provides a quantitative methodology and fundamental knowledge to further explore the role of oxidative stress in antibiotics-meditated bacterial death and to assess physiological changes associated with the complex metabolic events related to oxidative stress and bacterial resistance.
authors.affiliation: Department of Chemistry & Biomolecular Science, Clarkson University, 8 Clarkson Avenue, Potsdam, NY 13699-5810, USA.
authors.forename: Xiaobo
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Chemistry & Biomolecular Science, Clarkson University, 8 Clarkson Avenue, Potsdam, NY 13699-5810, USA; University of Carthage, Laboratoire d'Ecologie et Technologie Microbienne (LETMi), Institut National des Sciences Appliquées et de Technologie (INSAT), 1080 Tunis, Tunisia; Tunis El Manar University, Higher Institute of Applied Biological Science of Tunis (ISSBAT), 1006 Tunis, Tunisia.
authors.forename: Mouna
authors.initials: M
authors.lastname: Marrakchi
authors.affiliation: Department of Civil and Environmental Engineering, Clarkson University, 8 Clarkson Avenue, Potsdam, NY 13699-5710, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Jahne
authors.affiliation: Department of Civil and Environmental Engineering, Clarkson University, 8 Clarkson Avenue, Potsdam, NY 13699-5710, USA.
authors.forename: Shane
authors.initials: S
authors.lastname: Rogers
authors.affiliation: Department of Chemistry & Biomolecular Science, Clarkson University, 8 Clarkson Avenue, Potsdam, NY 13699-5810, USA. Electronic address: eandrees@clarkson.edu.
authors.forename: Silvana
authors.initials: S
authors.lastname: Andreescu
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000378:metabolism; D015374:Biosensing Techniques; D002138:Calibration; D024881:Drug Resistance, Bacterial; D055664:Electrochemical Techniques; D004566:Electrodes; D004926:Escherichia coli / Q000187:drug effects / Q000378:metabolism; D008089:Listeria monocytogenes / Q000187:drug effects / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D018384:Oxidative Stress; D013482:Superoxide Dismutase / Q000378:metabolism; D013481:Superoxides / Q000032:analysis* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D013481:Superoxides; D013482:Superoxide Dismutase
keywords: Antibiotic resistance; Bacteria; Electrochemical cytochrome c biosensor; Oxidative stress; Reactive oxygen species; Superoxide radicals; Superoxide release