title: Copper as an antimicrobial agent against opportunistic pathogenic and multidrug resistant Enterobacter bacteria.
abstract: Infections by Enterobacter species are common and are multidrug resistant. The use of bactericidal surface materials such as copper has lately gained attention as an effective antimicrobial agent due to its deadly effects on bacteria, yeast, and viruses. The aim of the current study was to assess the antibacterial activity of copper surfaces against Enterobacter species. The antibacterial activity of copper surfaces was tested by overlying 5×10(6) CFU/ml suspensions of representative Enterobacter strains and comparing bacterial survival counts on copper surfaces at room temperature. Iron, stainless steel, and polyvinylchloride (PVC) were used as controls. The mechanisms responsible for bacterial killing on copper surfaces were investigated by a mutagenicity assay of the D-cycloserin (cyclA gene), single cell gel electrophoresis, a staining technique, and inductively coupled plasma mass spectroscopy. Copper yielded a significant decrease in the viable bacterial counts at 2 h exposure and a highly significant decrease at 4 h. Loss of cell integrity and a significantly higher influx of copper into bacterial cells exposed to copper surfaces, as compared to those exposed to the controls, were documented. There was no increase in mutation rate and DNA damage indicating that copper contributes to bacterial killing by adversely affecting cellular structure without directly targeting the genomic DNA. These findings suggest that copper's antibacterial activity against Enterobacter species could be utilized in health care facilities and in food processing plants to reduce the bioburden, which would increase protection for susceptible members of the community.
authors.affiliation: State Key Laboratory of Rice Biology and Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 310058 Hangzhou, P. R. China.
authors.forename: Wen-Xiao
authors.initials: WX
authors.lastname: Tian
authors.forename: Shi
authors.initials: S
authors.lastname: Yu
authors.forename: Muhammad
authors.initials: M
authors.lastname: Ibrahim
authors.forename: Abdul Wareth
authors.initials: AW
authors.lastname: Almonaofy
authors.forename: Liu
authors.initials: L
authors.lastname: He
authors.forename: Qiu
authors.initials: Q
authors.lastname: Hui
authors.forename: Zhu
authors.initials: Z
authors.lastname: Bo
authors.forename: Bin
authors.initials: B
authors.lastname: Li
authors.forename: Guan-Lin
authors.initials: GL
authors.lastname: Xie
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology*; D015169:Colony Count, Microbial; D003300:Copper / Q000494:pharmacology*; D003523:Cycloserine / Q000633:toxicity; D024901:Drug Resistance, Multiple, Bacterial / Q000187:drug effects*; D004586:Electrophoresis; D004754:Enterobacter / Q000187:drug effects*; D013058:Mass Spectrometry; D050296:Microbial Viability / Q000187:drug effects; D013194:Staining and Labeling; D013696:Temperature; D013997:Time Factors
chemical_list: D000890:Anti-Infective Agents; D003300:Copper; D003523:Cycloserine