title: Antimicrobial copper alloy surfaces are effective against vegetative but not sporulated cells of gram-positive Bacillus subtilis.
abstract: This study explores the role of membrane phospholipid peroxidation in the copper alloy mediated contact killing of Bacillus subtilis, a spore-forming gram-positive bacterial species. We found that B. subtilis endospores exhibited significant resistance to copper alloy surface killing but vegetative cells were highly sensitive to copper surface exposure. Cell death and lipid peroxidation occurred in B. subtilis upon copper alloy surface exposure. In a sporulation-defective strain carrying a deletion of almost the entire SpoIIA operon, lipid peroxidation directly correlated with cell death. Moreover, killing and lipid peroxidation initiated immediately and at a constant rate upon exposure to the copper surface without the delay observed previously in E. coli. These findings support the hypothesis that membrane lipid peroxidation is the initiating event causing copper surface induced cell death of B. subtilis vegetative cells. The findings suggest that the observed differences in the kinetics of copper-induced killing compared to E. coli result from differences in cell envelop structure. As demonstrated in E. coli, DNA degradation was shown to be a secondary effect of copper exposure in a B. subtilis sporulation-defective strain.
authors.affiliation: Department of Biological Sciences and Geology, Queensborough Community College - CUNY, 222-05 56th Avenue, Bayside, New York, 11364.
authors.forename: Kaungmyat
authors.initials: K
authors.lastname: San
authors.affiliation: Department of Biological Sciences and Geology, Queensborough Community College - CUNY, 222-05 56th Avenue, Bayside, New York, 11364.
authors.forename: Janet
authors.initials: J
authors.lastname: Long
authors.affiliation: Biology Department, Queens College - CUNY, 65-30 Kissena Boulevard, Flushing, New York, 11367.
authors.forename: Corinne A
authors.initials: CA
authors.lastname: Michels
authors.affiliation: Department of Biological Sciences and Geology, Queensborough Community College - CUNY, 222-05 56th Avenue, Bayside, New York, 11364.
authors.forename: Nidhi
authors.initials: N
authors.lastname: Gadura
mesh_terms: D000497:Alloys / Q000378:metabolism*; D000900:Anti-Bacterial Agents / Q000378:metabolism*; D001412:Bacillus subtilis / Q000187:drug effects*; D003300:Copper / Q000378:metabolism*; D015227:Lipid Peroxidation; D050296:Microbial Viability / Q000187:drug effects*; D010743:Phospholipids / Q000378:metabolism; D013171:Spores, Bacterial / Q000187:drug effects*
chemical_list: D000497:Alloys; D000900:Anti-Bacterial Agents; D010743:Phospholipids; D003300:Copper
keywords: Antimicrobial copper; lipid peroxidation; mechanism copper surface killing