Dissertation
Applications of electrochemical devices for antibiotic resistance detection and biofilm removal
Washington State University
Doctor of Philosophy (PhD), Washington State University
01/2022
DOI:
https://doi.org/10.7273/000004371
Handle:
https://hdl.handle.net/2376/118912
Abstract
The objectives of this dissertation were to develop electrochemical platforms for monitoring cellular respiration and removing pathogenic bacterial biofilms. My Ph.D. focused on two directions of pathogen treatment: electrochemical antibiotic susceptibility testing and electrochemically generated biocides for antibiotic-alternative biofilm removal. Electron transport within bacteria plays a critical role in respiration. The first objective was directly measuring changes in electron transport from bacteria to an electrode with antibiotic challenge as an indication of antibiotic susceptibility or resistance. An electron mediator (phenazine methosulfate) was provided to transport the electrons from bacteria to electrodes. Electrochemical measurements decreased the time for antibiotic susceptibility results from 48 h to less than 90 min when tested with four critical pathogens with four antibiotics: Staphylococcus aureus, Acinetobacter baumannii, Klebsiella pneumonia, and Escherichia coli treated with tobramycin, ciprofloxacin, imipenem, and oxacillin. Faster antibiotic susceptibility results could improve patient outcomes and antibiotic efficacy. The second objective of this dissertation was to study the efficacy, toxicity, and transport of hydrogen peroxide (H2O2) and hypochlorous (HOCl) in ex vivo S. aureus biofilms in a porcine explant biofilm model. H2O2 and HOCl non-specifically target cells and can permeate into the biofilm and explant. We showed that a H2O2-producing e-bandage strongly effected S. aureus colonization and removed 5.4 log10 CFU/cm2 of a young biofilm with a 24 h treatments. The HOCl-producing e-bandage was even more effective, completely inhibiting S. aureus infection with a 12 h treatment and significantly removing mature biofilms with 6, 12, and 24 h treatments. Both H2O2 and HOCl permeated the hydrogel atop the explants and into the explant/biofilm by 300 µm. Toxicity of the e-bandages was also assessed, with a 33% reduction in viability when an H2O2-producing e-bandage was applied on day three and an average reduction of 64% with the HOCl-producing e-bandage, regardless of treatment time or day. Overall, the conclusions of these studies were that antibiotic susceptibility testing can be expedited by electrochemically monitoring cellular respiration and that electrochemically generated biocides are effective at removing ex vivo S. aureus biofilms.
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Details
- Title
- Applications of electrochemical devices for antibiotic resistance detection and biofilm removal
- Creators
- Gretchen Tibbits
- Contributors
- Haluk Beyenal (Advisor)Nathalie Wall (Committee Member)Steven Saunders (Committee Member)Jerome Babauta (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Voiland College of Engineering and Architecture
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 293
- Identifiers
- 99900883134501842
- Language
- English
- Resource Type
- Dissertation