title: Mechanisms of Inactivation by High-Voltage Atmospheric Cold Plasma Differ for Escherichia coli and Staphylococcus aureus.
abstract: Atmospheric cold plasma (ACP) is a promising nonthermal technology effective against a wide range of pathogenic microorganisms. Reactive oxygen species (ROS) play a crucial inactivation role when air or other oxygen-containing gases are used. With strong oxidative stress, cells can be damaged by lipid peroxidation, enzyme inactivation, and DNA cleavage. Identification of ROS and an understanding of their role are important for advancing ACP applications for a range of complex microbiological issues. In this study, the inactivation efficacy of in-package high-voltage (80 kV [root mean square]) ACP (HVACP) and the role of intracellular ROS were investigated. Two mechanisms of inactivation were observed in which reactive species were found to either react primarily with the cell envelope or damage intracellular components. Escherichia coli was inactivated mainly by cell leakage and low-level DNA damage. Conversely, Staphylococcus aureus was mainly inactivated by intracellular damage, with significantly higher levels of intracellular ROS observed and little envelope damage. However, for both bacteria studied, increasing treatment time had a positive effect on the intracellular ROS levels generated.
authors.affiliation: School of Food Science and Environmental Health, Dublin Institute of Technology, Dublin, Ireland.
authors.forename: L
authors.initials: L
authors.lastname: Han
authors.affiliation: School of Food Science and Environmental Health, Dublin Institute of Technology, Dublin, Ireland.
authors.forename: S
authors.initials: S
authors.lastname: Patil
authors.affiliation: School of Food Science and Environmental Health, Dublin Institute of Technology, Dublin, Ireland.
authors.forename: D
authors.identifier: http://orcid.org/0000-0003-3188-5115
authors.initials: D
authors.lastname: Boehm
authors.affiliation: School of Food Science and Environmental Health, Dublin Institute of Technology, Dublin, Ireland.
authors.forename: V
authors.initials: V
authors.lastname: Milosavljević
authors.affiliation: School of Food Science and Environmental Health, Dublin Institute of Technology, Dublin, Ireland School of Chemical Engineering, UNSW, Sydney, Australia.
authors.forename: P J
authors.initials: PJ
authors.lastname: Cullen
authors.affiliation: School of Food Science and Environmental Health, Dublin Institute of Technology, Dublin, Ireland paula.bourke@dit.ie.
authors.forename: P
authors.initials: P
authors.lastname: Bourke
mesh_terms: D004249:DNA Damage / Q000187:drug effects; D004203:Disinfection / Q000295:instrumentation / Q000379:methods*; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D050296:Microbial Viability / Q000187:drug effects; D058626:Plasma Gases / Q000633:toxicity*; D017382:Reactive Oxygen Species / Q000378:metabolism; D013211:Staphylococcus aureus / Q000187:drug effects / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism
chemical_list: D058626:Plasma Gases; D017382:Reactive Oxygen Species