Exposure of bacterial biofilms to electrical current leads to cell death mediated in part by reactive oxygen species

Cassandra L. Brinkman, Suzannah M. Schmidt-Malan, Melissa J. Karau, Kerryl Greenwood-Quaintance, Daniel J. Hassett, Jayawant Mandrekar, Robin Patel

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Bacterial biofilms may form on indwelling medical devices such as prosthetic joints, heart valves and catheters, causing challenging-to-treat infections. We have previously described the 'electricidal effect', in which bacterial biofilms are decreased following exposure to direct electrical current. Herein, we sought to determine if the decreased bacterial quantities are due to detachment of biofilms or cell death and to investigate the role that reactive oxygen species (ROS) play in the observed effect. Using confocal and electron microscopy and flow cytometry, we found that direct current (DC) leads to cell death and changes in the architecture of biofilms formed by Gram-positive and Gram-negative bacteria. Reactive oxygen species (ROS) appear to play a role in DC-associated cell death, as there was an increase in ROS-production by Staphylococcus aureus and Staphylococcus epidermidis biofilms following exposure to DC. An increase in the production of ROS response enzymes catalase and superoxide dismutase (SOD) was observed for S. aureus, S. epidermidis and Pseudomonas aeruginosa biofilms following exposure to DC. Additionally, biofilms were protected from cell death when supplemented with antioxidants and oxidant scavengers, including catalase, mannitol and Tempol. Knocking out SOD (sodAB) in P. aeruginosa led to an enhanced DC effect. Microarray analysis of P. aeruginosa PAO1 showed transcriptional changes in genes related to the stress response and cell death. In conclusion, the electricidal effect results in death of bacteria in biofilms, mediated, at least in part, by production of ROS.

Original languageEnglish (US)
Article numbere0168595
JournalPLoS One
Volume11
Issue number12
DOIs
StatePublished - Dec 1 2016

Fingerprint

electric current
Biofilms
Cell death
biofilm
cell death
reactive oxygen species
Reactive Oxygen Species
Cell Death
Pseudomonas aeruginosa
Staphylococcus epidermidis
Catalase
Staphylococcus aureus
catalase
Bacteria
heart valves
Cardiac Catheters
medical equipment
Flow cytometry
Confocal microscopy
Catheters

ASJC Scopus subject areas

  • Medicine(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)

Cite this

Exposure of bacterial biofilms to electrical current leads to cell death mediated in part by reactive oxygen species. / Brinkman, Cassandra L.; Schmidt-Malan, Suzannah M.; Karau, Melissa J.; Greenwood-Quaintance, Kerryl; Hassett, Daniel J.; Mandrekar, Jayawant; Patel, Robin.

In: PLoS One, Vol. 11, No. 12, e0168595, 01.12.2016.

Research output: Contribution to journalArticle

Brinkman, Cassandra L. ; Schmidt-Malan, Suzannah M. ; Karau, Melissa J. ; Greenwood-Quaintance, Kerryl ; Hassett, Daniel J. ; Mandrekar, Jayawant ; Patel, Robin. / Exposure of bacterial biofilms to electrical current leads to cell death mediated in part by reactive oxygen species. In: PLoS One. 2016 ; Vol. 11, No. 12.
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