Eradicating Candida auris through Physiological Stress and Drug Permeation using Low-Level DCs
Discipline: Technology and Engineering
Subcategory: Biomedical Engineering
Session: 2
Room: L'efant Plaza
Camila S. Cué Royo - Carnegie Mellon University
Co-Author(s): Colin Landis, University of Pittsburgh, PA; Maria Geraghty, University of Pittsburgh, PA; Sricharani Rao Balmuri, University of Pittsburgh, PA; Tagbo H. R. Niepa, Carnegie Mellon University, PA
The rise of multi-drug resistant microorganisms (MDROs) has become a global threat, leading to prolonged illnesses, treatment failures, and fatal outcomes. The challenges presented by MDROs have prompted research into innovative solutions, where electrochemical therapy (ECT) shows a promising alternative to conventional treatments. Candida auris (C. auris), a yeast causing severe illness in hospitalized patients, has raised serious concerns due to its resistance to various antifungals. This study explores ECT as a novel solution against C. auris, investigating the impact of low-level direct currents (DCs) on cell viability, morphology, functions, and antifungal potentiation. A solution containing C. auris cells was exposed to ECT treatments for 1h using three current densities (17.5, 35, and 70 μA/cm2 DC). Cell viability was evaluated during the treatment using colony-forming units (CFUs), where 70 μA/cm2 DC resulted in the highest efficacy, with nearly complete cell death. Scanning electron microscopy (SEM) was used to assess the effects of ECT on cell morphology, revealing significant cell damage following the treatment with 70 μA/cm2 DC. The impact on cell metabolism was determined through the formation of red cylindrical intravacuolar structures (CIVS) following FUN1 staining. Comparing to untreated cells, ECT-treated cells lacked CIVS, suggesting alterations in the metabolic state. Additionally, performing flow cytometry analyses using Rhodamine 123 and H2DCFDA allowed access to ECT’s effect on membrane potential and intracellular levels of reactive oxygen species (ROS). Histograms revealed a higher fluorescence in ECT-treated cells, indicating ECT-infused alterations on cellular functions. Furthermore, the combined effect of ECT and antifungal was examined from time-dependent diffusion studies using BODIPY-labeled Caspofungin (CSF-BOD) and confocal microscopy. ECT-treated cells showed rapid drug adherence after 5 minutes with significant Caspofungin uptake after 15 minutes. In contrast, untreated cells exhibited minimal drug uptake after 60 minutes. These findings demonstrate that ECT is a promising alternative for addressing MDROs like C. auris. Future research aims to explore mechanisms to implement ECT through medical devices and combat difficult-to-treat infections.References: Center for Disease Control and Prevention (2019). “General Information about Candida auris.” Retrieved November 30, 2021, from https://www.cdc.gov/fungal/candida-auris/candida-auris-qanda.html.Parry-Nweye, E., et al. (2019). “Electrochemical strategy for eradicating fluconazole-tolerant Candida albicans using implantable titanium.” ACS applied materials & interfaces 11(44): 40997-41008.Jaber, Q. Z., et al. (2020). “Elevated vacuolar uptake of fluorescently labeled antifungal drug caspofungin predicts echinocandin resistance in pathogenic yeast.” ACS Central Science 6(10): 1698-1712.
Funder Acknowledgement(s): This study was supported, in part, by a grant from NSF (CMMI-2144253) awarded to Tagbo H. R. Niepa, PhD, Carnegie Mellon University, Pittsburgh, PA.This study was supported, in part, by a grant from NIH (S10OD030254-01A1) awarded to Robert Gibbs, PhD, Director of Cell Imaging Core, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA
Faculty Advisor: Dr. Tagbo H. R. Niepa, tniepa@andrew.cmu.edu
Role: For this research, I administered low-level direct current treatments to investigate the impact of ECT on C. auris cell viability, morphology, metabolic state, membrane potential, and ROS generation, employing the following techniques: CFUs, SEM, confocal microscopy, and flow cytometry analysis.