Copper Continuously Limits the Concentration of Bacteria Resident on Bed Rails within the Intensive Care Unit

Schmidt, Michael G.; Attaway, Hubert H.; Fairey, Sarah E.; Steed, Lisa L.; Michels, Harold T.; Salgado, Cassandra D.

doi:10.1086/670224

Cited by 82 publications

(74 citation statements)

References 12 publications

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“…Recent clinical trials showed that covering hightouch surfaces in hospital rooms with copper can significantly decrease the bacterial burden and can reduce the number of hospital-acquired infections by more than 50% (35,(45)(46)(47)(48). Because A. baumannii fomite-associated hospital outbreaks have been documented, specifically from a contaminated hospital bed and burn theater, evidence that copper effectively eliminates environmental A. baumannii is important (49).…”

Section: Figmentioning

confidence: 99%

Copper Resistance of the Emerging Pathogen Acinetobacter baumannii

Williams

Neu

Gilbreath

et al. 2016

Appl Environ Microbiol

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Acinetobacter baumannii is an important emerging pathogen that is capable of causing many types of severe infection, especially in immunocompromised hosts. Since A. baumannii can rapidly acquire antibiotic resistance genes, many infections are on the verge of being untreatable, and novel therapies are desperately needed. To investigate the potential utility of copper-based antibacterial strategies against Acinetobacter infections, we characterized copper resistance in a panel of recent clinical A. baumannii isolates. Exposure to increasing concentrations of copper in liquid culture and on solid surfaces resulted in dose-dependent and strain-dependent effects; levels of copper resistance varied broadly across isolates, possibly resulting from identified genotypic variation among strains. Examination of the growth-phase-dependent effect of copper on A. baumannii revealed that resistance to copper increased dramatically in stationary phase. Moreover, A. baumannii biofilms were more resistant to copper than planktonic cells but were still susceptible to copper toxicity. Exposure of bacteria to subinhibitory concentrations of copper allowed them to better adapt to and grow in high concentrations of copper; this copper tolerance response is likely achieved via increased expression of copper resistance mechanisms. Indeed, genomic analysis revealed numerous putative copper resistance proteins that share amino acid homology to known proteins in Escherichia coli and Pseudomonas aeruginosa. Transcriptional analysis revealed significant upregulation of these putative copper resistance genes following brief copper exposure. Future characterization of copper resistance mechanisms may aid in the search for novel antibiotics against Acinetobacter and other highly antibiotic-resistant pathogens. IMPORTANCEAcinetobacter baumannii causes many types of severe nosocomial infections; unfortunately, some isolates have acquired resistance to almost every available antibiotic, and treatment options are incredibly limited. Copper is an essential nutrient but becomes toxic at high concentrations. The inherent antimicrobial properties of copper give it potential for use in novel therapeutics against drug-resistant pathogens. We show that A. baumannii clinical isolates are sensitive to copper in vitro, both in liquid and on solid metal surfaces. Since bacterial resistance to copper is mediated though mechanisms of efflux and detoxification, we identified genes encoding putative copper-related proteins in A. baumannii and showed that expression of some of these genes is regulated by the copper concentration. We propose that the antimicrobial effects of copper may be beneficial in the development of future therapeutics that target multidrug-resistant bacteria.

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Section: Figmentioning

confidence: 99%

Copper Resistance of the Emerging Pathogen Acinetobacter baumannii

Williams

Neu

Gilbreath

et al. 2016

Appl Environ Microbiol

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“…Their antimicrobial properties are now well established, and copper has been recently registered at the U.S. Environmental Protection Agency as the first solid antimicrobial material . Several studies have been conducted to evaluate the antimicrobial efficacy of surfaces composed of Cu or Cu alloys, both in vitro and in the clinical setting Schmidt et al 2013). Issues regarding the variation in the constituents of Cu alloys and the stability of Cu-impregnated surfaces have, however, raised concerns about the practicality of using Cu as selfsanitation material on flexible surfaces (Torres et al 2010).…”

Section: Introductionmentioning

confidence: 99%

Bactericidal activity and mechanism of action of copper-sputtered flexible surfaces against multidrug-resistant pathogens

Ballo

Rtimi

Mancini

et al. 2016

Appl Microbiol Biotechnol

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Using direct current magnetron sputtering (DCMS), we generated flexible copper polyester surfaces (Cu-PES) and investigated their antimicrobial activity against a range of multidrug-resistant (MDR) pathogens including eight Gram-positive isolates (three methicillin-resistant Staphylococcus aureus [MRSA], four vancomycin-resistant enterococci, one methicillin-resistant Staphylococcus epidermidis) and four Gram-negative strains (one extended-spectrum β-lactamase-producing [ESBL] Escherichia coli, one ESBL Klebsiella pneumoniae, one imipenem-resistant Pseudomonas aeruginosa, and one ciprofloxacin-resistant Acinetobacter baumannii). Bactericidal activity (≥3 log10 CFU reduction of the starting inoculum) was reached within 15-30 min exposure to Cu-PES. Antimicrobial activity of Cu-PES persisted in the absence of oxygen and against both Gram-positive and Gram-negative bacteria containing elevated levels of catalases, indicating that reactive oxygen species (ROS) do not play a primary role in the killing process. The decrease in cell viability of MRSA ATCC 43300 and Enterococcus faecalis V583 correlated with the progressive loss of cytoplasmic membrane integrity both under aerobic and anaerobic conditions, suggesting that Cu-PES mediated killing is primarily induced by disruption of the cytoplasmic membrane function. Overall, we here present novel antimicrobial copper surfaces with improved stability and sustainability and provide further insights into their mechanism of killing.

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“…6,7 They also have been shown to continuously reduce the concentration of total bacteria on bed rails within intensive care unit (ICU) rooms. 8 The present study was designed to assess the effectiveness of ABS-G2015 (Allied BioScience, Point Roberts, WA), a formulation of a quaternary ammonium organosilane compound that binds to surfaces and produces a residual (ie, long-term) disinfecting activity. Our initial laboratory work demonstrated ABS-G2015's effectiveness against a wide range of pathogenic bacteria (eg, MRSA, Pseudomonas aeruginosa) and viruses (eg, MS-2 virus).…”

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confidence: 99%