title: Spatial Dependence of DNA Damage in Bacteria due to Low-Temperature Plasma Application as Assessed at the Single Cell Level.
abstract: Low temperature plasmas (LTPs) generate a cocktail of reactive nitrogen and oxygen species (RNOS) with bactericidal activity. The RNOS however are spatially unevenly distributed in the plasma. Here we test the hypothesis that this distribution will affect the mechanisms underpinning plasma bactericidal activity focussing on the level of DNA damage in situ. For the first time, a quantitative, single cell approach was applied to assess the level of DNA damage in bacteria as a function of the radial distance from the centre of the plasma jet. Salmonella enterica on a solid, dry surface was treated with two types of LTP: an atmospheric-pressure dielectric barrier discharge plasma jet (charged and neutral species) and a radio-frequency atmospheric-pressure plasma jet (neutral species). In both cases, there was an inverse correlation between the degree of DNA damage and the radial distance from the centre of the plasma, with the highest DNA damage occurring directly under the plasma. This trend was also observed with Staphylococcus aureus. LTP-generated UV radiation was eliminated as a contributing factor. Thus valuable mechanistic information can be obtained from assays on biological material, which can inform the development of LTP as a complementary or alternative therapy for (topical) bacterial infections.
authors.affiliation: Centre for Immunology and Infection, Department of Biology and Hull York Medical School, University of York, York, U.K.|York Plasma Institute, Department of Physics, University of York, York, U.K.
authors.forename: Angela
authors.initials: A
authors.lastname: Privat-Maldonado
authors.affiliation: York Plasma Institute, Department of Physics, University of York, York, U.K.
authors.forename: Deborah
authors.initials: D
authors.lastname: O'Connell
authors.affiliation: Centre for Immunology and Infection, Department of Biology and Hull York Medical School, University of York, York, U.K.
authors.forename: Emma
authors.initials: E
authors.lastname: Welch
authors.affiliation: York Plasma Institute, Department of Physics, University of York, York, U.K.
authors.forename: Roddy
authors.initials: R
authors.lastname: Vann
authors.affiliation: Centre for Immunology and Infection, Department of Biology and Hull York Medical School, University of York, York, U.K.
authors.forename: Marjan W
authors.initials: MW
authors.lastname: van der Woude
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004249:DNA Damage; D050296:Microbial Viability / Q000187:drug effects; D058626:Plasma Gases / Q000494:pharmacology*; D019779:Salmonella enterica / Q000187:drug effects* / Q000502:physiology; D059010:Single-Cell Analysis; D062206:Spatial Analysis; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000502:physiology
chemical_list: D000900:Anti-Bacterial Agents; D058626:Plasma Gases