title: Contact killing of bacteria on copper is suppressed if bacterial-metal contact is prevented and is induced on iron by copper ions.
abstract: Bacteria are rapidly killed on copper surfaces, and copper ions released from the surface have been proposed to play a major role in the killing process. However, it has remained unclear whether contact of the bacteria with the copper surface is also an important factor. Using laser interference lithography, we engineered copper surfaces which were covered with a grid of an inert polymer which prevented contact of the bacteria with the surface. Using Enterococcus hirae as a model organism, we showed that the release of ionic copper from these modified surfaces was not significantly reduced. In contrast, killing of bacteria was strongly attenuated. When E. hirae cells were exposed to a solid iron surface, the loss of cell viability was the same as on glass. However, exposing cells to iron in the presence of 4 mM CuSO4 led to complete killing in 100 min. These experiments suggest that contact killing proceeds by a mechanism whereby the metal-bacterial contact damages the cell envelope, which, in turn, makes the cells susceptible to further damage by copper ions.
authors: Department of Clinical Research, University of Bern, Bern, Switzerland.
authors: Salima
authors: S
authors: Mathews
authors: Michael
authors: M
authors: Hans
authors: Frank
authors: F
authors: Mücklich
authors: Marc
authors: M
authors: Solioz
mesh_terms: D002412:Cations / Q000494:pharmacology*; D002462:Cell Membrane / Q000187:drug effects; D003300:Copper / Q000494:pharmacology*; D016983:Enterococcus / Q000187:drug effects*; D007501:Iron / Q000494:pharmacology*; D050296:Microbial Viability / Q000187:drug effects
chemical_list: D002412:Cations; D003300:Copper; D007501:Iron
references: Appl Environ Microbiol. 2010 Aug;76(16):5390-401
references: 20581191
references: Microbiologyopen. 2012 Mar;1(1):46-52
references: 22950011
references: J Appl Microbiol. 2009 May;106(5):1448-55
references: 19239551
references: Appl Environ Microbiol. 2012 May;78(10):3614-21
references: 22344668
references: Appl Environ Microbiol. 2008 Feb;74(4):977-86
references: 18156321
references: BMC Microbiol. 2004 Apr 30;4:19
references: 15119960
references: J Mater Sci Mater Med. 2008 Sep;19(9):3057-62
references: 18392666
references: Environ Sci Technol. 2012 Oct 16;46(20):11299-304
references: 22998466
references: Appl Microbiol. 1975 Jun;29(6):807-13
references: 16350018
references: Infect Control Hosp Epidemiol. 2012 Feb;33(2):200-1
references: 22227992
references: J Hosp Infect. 2006 Jul;63(3):289-97
references: 16650507
references: Int J Nanomedicine. 2011;6:1833-52
references: 21931480
references: Nanomedicine. 2007 Mar;3(1):95-101
references: 17379174
references: Biometals. 2011 Jun;24(3):429-44
references: 21384090
references: J Hosp Infect. 2008 Jan;68(1):45-51
references: 18069086
references: J Microbiol. 2012 Aug;50(4):586-93
references: 22923106
references: Appl Environ Microbiol. 2011 Feb;77(3):794-802
references: 21148701
references: J Hosp Infect. 2008 Feb;68(2):145-51
references: 18207284
references: Proc Natl Acad Sci U S A. 2009 May 19;106(20):8344-9
references: 19416816
references: Int J Food Microbiol. 2006 Sep 1;111(2):93-8
references: 16876278
references: J Hosp Infect. 2012 Aug;81(4):217-23
references: 22738611
references: Appl Environ Microbiol. 2006 Jun;72(6):4239-44
references: 16751537
references: J Hosp Infect. 2010 Jan;74(1):72-7
references: 19931938
references: Antonie Van Leeuwenhoek. 2002 Aug;82(1-4):187-216
references: 12369188
references: J Clin Microbiol. 2012 Jul;50(7):2217-23
references: 22553242
references: Appl Environ Microbiol. 2012 Mar;78(6):1776-84
references: 22247141
references: Appl Environ Microbiol. 2011 Sep;77(17):6049-59
references: 21742916
references: Int J Food Microbiol. 2005 Dec 15;105(3):445-54
references: 16253366
references: J Hosp Infect. 2007 Nov;67(3):271-7
references: 17950486
references: Appl Environ Microbiol. 2010 Mar;76(5):1341-8
references: 20048058
references: Appl Microbiol Biotechnol. 2011 Mar;89(6):1963-70
references: 21085951
references: J Appl Microbiol. 2010 Dec;109(6):2200-5
references: 21040269
references: J Appl Microbiol. 2013 Mar;114(3):680-7
references: 23228103
references: Appl Environ Microbiol. 2011 Mar;77(5):1541-7
references: 21193661
references: Appl Environ Microbiol. 2011 Jan;77(2):416-26
references: 21097600
references: Appl Environ Microbiol. 2010 Jun;76(12):4099-101
references: 20418419
references: Appl Microbiol Biotechnol. 2010 Aug;87(5):1875-9
references: 20449737
references: FEMS Microbiol Lett. 2012 Jun;331(2):160-4
references: 22486165
references: Environ Microbiol. 2012 Jul;14(7):1730-43
references: 22176893