title: Antibiofilm and membrane-damaging potential of cuprous oxide nanoparticles against Staphylococcus aureus with reduced susceptibility to vancomycin.
abstract: The antimicrobial effects of copper ions and salts are well known, but the effects of cuprous oxide nanoparticles (Cu2O-NPs) on staphylococcal biofilms have not yet been clearly revealed. The present study evaluated Cu2O-NPs for their antibacterial and antibiofilm activities against heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) and vancomycin-intermediate S. aureus (VISA). Nanoscaled Cu2O, generated by solution phase technology, contained Cu2O octahedral nanoparticles. Field emission electron microscopy demonstrated particles with sizes ranging from 100 to 150 nm. Cu2O-NPs inhibited the growth of S. aureus and showed antibiofilm activity. The MICs and minimum biofilm inhibitory concentrations ranged from 625 μg/ml to 5,000 μg/ml and from 2,500 μg/ml to 10,000 μg/ml, respectively. Exposure of S. aureus to Cu2O-NPs caused leakage of the cellular constituents and increased uptake of ethidium bromide and propidium iodide. Exposure also caused a significant reduction in the overall vancomycin-BODIPY (dipyrromethene boron difluoride [4,4-difluoro-4-bora-3a,4a-diaza-s-indacene] fluorescent dye) binding and a decrease in the viable cell count in the presence of 7.5% sodium chloride. Cu2O-NP toxicity assessment by hemolysis assay showed no cytotoxicity at 625 to 10,000 μg/ml concentrations. The results suggest that Cu2O-NPs exert their action by disruption of the bacterial cell membrane and can be used as effective antistaphylococcal and antibiofilm agents in diverse medical devices.
authors: Department of Microbiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India Amity Institute of Biotechnology, Amity University Uttar Pradesh, Lucknow, India.
authors: Avinash
authors: A
authors: Singh
authors: Department of Chemistry, Indian Institute of Technology, Kanpur, India.
authors: Asar
authors: A
authors: Ahmed
authors: Department of Microbiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India kashinprasad@gmail.com.
authors: Kashi N
authors: KN
authors: Prasad
authors: Department of Microbiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India.
authors: Sonali
authors: S
authors: Khanduja
authors: Department of Microbiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India.
authors: Satyendra K
authors: SK
authors: Singh
authors: Amity Institute of Biotechnology, Amity University Uttar Pradesh, Lucknow, India.
authors: Janmejai K
authors: JK
authors: Srivastava
authors: Department of Chemistry, Indian Institute of Technology, Kanpur, India.
authors: Namdeo S
authors: NS
authors: Gajbhiye
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects*; D003300:Copper / Q000737:chemistry* / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D008855:Microscopy, Electron, Scanning; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D013211:Staphylococcus aureus / Q000187:drug effects*; D014640:Vancomycin / Q000494:pharmacology*; D014961:X-Ray Diffraction
chemical_list: D000900:Anti-Bacterial Agents; D014640:Vancomycin; D003300:Copper; C000520:cuprous oxide