Dowody naukowe

Prace naukowe na temat przeciwdrobnoustrojowych właściwości metali na bazie miedzi.

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Physicochemical properties of copper important for its antibacterial activity and development of a unified model
Michael Hans, Salima Mathews, Frank Mücklich and Marc Solioz, Biointerphases 11, 018902 (2016);

Contact killing is a novel term describing the killing of bacteria when they come in contact with metallic copper or copper-containing alloys. In recent years, the mechanism of contact killing has received much attention and many mechanistic details are available. The authors here review some of these mechanistic aspects with a focus on the critical physicochemical properties of copper which make it antibacterial. Known mechanisms of contact killing are set in context to ionic, corrosive, and physical properties of copper. The analysis reveals that the oxidation behavior of copper, paired with the solubility properties of copper oxides, are the key factors which make metallic copper antibacterial. The concept advanced here explains the unique position of copper as an antibacterial metal. Based on our model, novel design criteria for metallic antibacterial materials may be derived.

Copper Surfaces are Associated with Significantly Lower Concentrations of Bacteria on Selected Surfaces within a Pediatric Intensive Care Unit
Michael G. Schmidt PhD; Bettina von Dessauer MD; Carmen Benavente MD; Dona Benadof MD; Paulina Cifuentes RN; Alicia Elgueta RN; Claudia Duran MS; Maria S. Navarrete MD MPH. American Journal of Infection Control, Corrected proof. doi:10.1016/j.ajic.2015.09

Background: Health careeassociated infections result in significant patient morbidity and mortality. Although cleaning can remove pathogens present on hospital surfaces, those surfaces may be inadequately
cleaned or recontaminated within minutes. Because of copper’s inherent and continuous antimicrobial properties, copper surfaces offer a solution to complement cleaning. The objective of this study was to quantitatively assess the bacterial microbial burden coincident with an assessment of the ability of antimicrobial copper to limit the microbial burden associated with 3 surfaces in a pediatric intensive care unit.

Methods: A pragmatic trial was conducted enrolling 1,012 patients from 2 high acuity care units within a 249-bed tertiary care pediatric hospital over 12 months. The microbial burden was determined from 3 frequently encountered surfaces, regardless of room occupancy, twice monthly, from 16 rooms, 8 outfitted normally and 8 outfitted with antimicrobial copper.

Results: Copper surfaces were found to be equivalently antimicrobial in pediatric settings to activities reported for adult medical intensive care units. The log10 reduction to the microbial burden from
antimicrobial copper surfaced bed rails was 1.996 (99%). Surprisingly, introduction of copper objects to 8 study rooms was found to suppress the microbial burden recovered from objects assessed in control
rooms by log10 of 1.863 (73%).

Conclusion: Copper surfaces warrant serious consideration when contemplating the introduction of no-touch disinfection technologies for reducing burden to limit acquisition of HAIs.

Human Coronavirus 229E Remains Infectious on Common Touch Surface Materials
Warnes SL, Little ZR, Keevil CW. 2015. Human coronavirus 229E remains infectious on common touch surface materials. mBio 6(6):e01697-15. doi:10.1128/mBio.01697-15.

The evolution of new and reemerging historic virulent strains of respiratory viruses from animal reservoirs is a significant threat to human health. Inefficient human-to-human transmission of zoonotic strains may initially limit the spread of transmission, but an infection may be contracted by touching contaminated surfaces. Enveloped viruses are often susceptible to environmental stresses, but the human coronaviruses responsible for severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) have recently caused increasing concern of contact transmission during outbreaks. We report here that pathogenic human coronavirus 229E remained infectious in a human lung cell culture model following at least 5 days of persistence on a range of common nonbiocidal surface materials, including polytetrafluoroethylene (Teflon; PTFE), polyvinyl chloride (PVC), ceramic tiles, glass, silicone rubber, and stainless steel. We have shown previously that noroviruses are destroyed on copper alloy surfaces. In this new study, human coronavirus 229E was rapidly inactivated on a range of copper alloys (within a few minutes for simulated fingertip contamination) and Cu/Zn brasses were very effective at lower copper concentration. Exposure to copper destroyed the viral genomes and irreversibly affected virus morphology, including disintegration of envelope and dispersal of surface spikes. Cu(I) and Cu(II) moieties were responsible for the inactivation, which was enhanced by reactive oxygen species generation on alloy surfaces, resulting in even faster inactivation than was seen with nonenveloped viruses on copper. Consequently, copper alloy surfaces could be employed in communal areas and at any mass gatherings to help reduce transmission of respiratory viruses from contaminated surfaces and protect the public health.

From Laboratory Research to a Clinical Trial: Copper Alloy Surfaces Kill Bacteria and Reduce Hospital-Acquired Infections
Michels, H.T. 2015. From Laboratory Research to a Clinical Trial: Copper Alloy Surfaces Kill Bacteria and Reduce Hospital-Acquired Infections. Health Environments Research & Design Journal. 1–16.

Bacteria die on copper alloy surfaces in both the laboratory and the hospital rooms. Infection rates were lowered in those hospital rooms containing copper components. Thus, based on the presented information, the placement of copper alloy components, in the built environment, may have the potential to reduce not only hospital-acquired infections but also patient treatment costs.

Antimicrobial Activity of Copper Alloys Against Invasive Multidrug-Resistant Nosocomial Pathogens
Koseoglu Eser O, Ergin A, Hascelik G, Current Microbiology, 5 June 2015

The emergence and spread of antibiotic resistance demanded novel approaches for the prevention of nosocomial infections, and metallic copper surfaces have been suggested as an alternative for the control of multidrug-resistant (MDR) bacteria in surfaces in the hospital environment.

This study aimed to evaluate the antimicrobial activity of copper material for invasive MDR nosocomial pathogens isolated over time, in comparison to stainless steel. Clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) (n:4), OXA-23 and OXA-58 positive, MDR Acinetobacter baumannii (n:6) and Pseudomonas aeruginosa (n:4) were evaluated.

The antimicrobial activity of coupons containing 99 % copper and a brass alloy containing 63 % copper was assessed against stainless steel. All the materials demonstrated statistically significant differences within each other for the logarithmic reduction of microorganisms. Among the three materials, the highest reduction of microorganisms was seen in 99 % copper and the least in stainless steel.

The result was statistically significant especially for 0, 2, and 4 h (P = 0.05). 99 % copper showed a bactericidal effect at less than 1 h for MRSA and at 2 h for P. aeruginosa. 63 % copper showed a bactericidal effect at 24 h for P. aeruginosa strains only. Stainless steel surfaces exhibited a bacteriostatic effect after 6 h for P. aeruginosa strains only.

99 % copper reduced the number of bacteria used significantly, produced a bactericidal effect and was more effective than 63 % copper.

The use of metallic copper material could aid in reducing the concentration of bacteria, especially for invasive nosocomial pathogens on hard surfaces in the hospital environment.

Destruction of the Capsid and Genome of GII.4 Human Norovirus Occurs During Exposure to Metal Alloys Containing Copper
C. S. Manuel, M. D. Moore and L.A. Jaykus, Applied and Environmental Microbiology, 15 May 2015

Human norovirus (HuNoV) represents a significant public health burden worldwide and can be environmentally transmitted. Copper surfaces have been shown to inactivate the cultivable surrogate murine norovirus, but no such data exist for HuNoV.

The purpose of this study was to characterize the destruction of GII.4 HuNoV and virus-like particles (VLPs) when exposed to copper alloy surfaces. Fecal suspensions positive for a GII.4 HuNoV outbreak strain or GII.4 virus-like particles (VLPs) were exposed to copper alloys or stainless steel for 0 to 240 min and recovered by elution. HuNoV genome integrity was assessed by RT-qPCR (without RNase treatment), and capsid integrity was assessed by RT-qPCR (with RNase treatment), transmission electron microscopy (TEM), SDS-PAGE/Western blot analysis, and a histo-blood group antigen (HBGA) binding assay.

Exposing fecal suspensions to pure copper for 60 min reduced GII.4 HuNoV RNA copy number by approximately 3 log 10 when analyzed by RT-qPCR without RNase treatment, and 4 log 10 when a prior RNase treatment was used.

The rate of reduction in HuNoV RNA copy number was approximately proportional to the percent copper in each alloy. Exposing GII.4 HuNoV VLPs to pure copper surfaces resulted in noticeable aggregation and destruction within 240 min, an 80% reduction in VP1 major capsid protein band intensity in 15 min, and near complete loss of HBGA receptor binding within 8 min. In all experiments, HuNoV remained stable on stainless steel.

These results suggest that copper surfaces destroy HuNoV, and may be useful in preventing environmental transmission of the virus in at-risk settings.

Antimicrobial Properties of Copper in Gram-Negative and Gram-Positive Bacteria
Meyer, T.J. 2015. Antimicrobial Properties of Copper in Gram-Negative and Gram-Positive Bacteria. International Journal of Biological, Biomolecular, Agricultural, Food and Biotechnological Engineering. Vol:9, No:3.

For centuries humans have used the antimicrobial properties of copper to their advantage. Yet, after all these years the underlying mechanisms of copper mediated cell death in various microbes remain unclear. We had explored the hypothesis that copper mediated increased levels of lipid peroxidation in the membrane fatty acids is responsible for increased killing in Escherichia coli.

In this study we show that in both gram positive (Staphylococcus aureus) and gram negative (Pseudomonas aeruginosa) bacteria there is a strong correlation between copper mediated cell death and increased levels of lipid peroxidation.

Interestingly, the non-spore forming gram positive bacteria as well as gram negative bacteria show similar patterns of cell death, increased levels of lipid peroxidation, as well as genomic DNA degradation, however there is some difference in loss in membrane integrity upon exposure to copper alloy surface.

Inactivation of murine norovirus on a range of copper alloy surfaces is accompanied by loss of capsid integrity
S. L. Warnes, E. N. Summersgill and C.W. Keevil, Applied and Environmental Microbiology, 1 December 2014

Norovirus is one of the most common causes of acute viral gastroenteritis. The virus is spread via faecal oral route, most commonly from infected food and water, but several outbreaks have originated from contamination of surfaces with infectious virus.

In this study a close surrogate of human norovirus causing gastrointestinal disease in mice, murine norovirus type 1 (MNV-1), retained infectivity for more than 2 weeks following contact with a range of surface materials including Teflon (polytetrafluoroethylene, PTFE), polyvinyl chloride (PVC), ceramic tiles, glass, silicone rubber and stainless steel. Persistence was, slightly prolonged on ceramic surfaces.

A previous study in our laboratory observed that copper and copper alloy dry surfaces rapidly inactivated MNV-1 and destroyed the viral genome. In this new study we have observed that a relatively small change in percentage copper, between 70-80% in copper nickels and 60-70% in brasses, had significant influence on the ability of the alloy to inactivate norovirus. Nickel alone did not affect virus but zinc did have some antiviral effect which had a synergistic effect with copper and resulted in increased efficacy of brasses at lower percentage copper.

Electron microscopy of purified MNV-1 that had been exposed to copper and stainless steel surfaces suggested a massive breakdown of the viral capsid had occurred on copper. In addition, MNV-1 that had been exposed to copper and treated with RNase demonstrated a reduction in viral gene copy number. This suggests capsid integrity is compromised on contact with copper, allowing copper ion access to the viral genome.

Inactivation of Bacterial and Viral Biothreat Agents on Metallic Copper Surfaces
Pauline Bleichert, Christophe Espirito Santo, Matthias Hanczaruk, Hermann Meyer, Gregor Grass, BioMetals, International Biometals Society, 7 August 2014

In recent years several studies in laboratory settings and in hospital environments have demonstrated that surfaces of massive metallic copper have intrinsic antibacterial and antiviral properties.  Microbes are rapidly inactivated by a quick, sharp shock known as contact killing.  The underlying mechanism is not yet fully understood; however, in this process the cytoplasmic membrane is severely damaged.  Pathogenic bacterial and viral high-consequence species able to evade the host immune system are among the most serious lethal microbial challenges to human health.  Here, we investigated contact-killing mediated by copper surfaces of Gram-negative bacteria (Brucella melitensis, Burkholderia mallei, Burkholderia pseudomallei, Francisella tularensis tularensis and Yersinia pestis) and of Gram-positive endospore-forming Bacillus anthracis.  Additionally, we also tested inactivation of monkeypox virus and vaccinia virus on copper.  This group of pathogens comprises biothreat species (or their close relatives) classified by the Center for Disease and Control and Prevention (CDC) as microbial select agents posing severe threats to public health and having the potential to be deliberately released.  All agents were rapidly inactivated on copper between 30 s and 5 min with the exception of B. anthracis endospores.  For vegetative bacterial cells prolonged contact to metallic copper resulted in the destruction of cell structure.

Enhancing Patient Safety through Strategic Placement of Copper Surfaces
M G Schmidt, C D Salgado, K A Sepkowitz, J F John, H H Attaway, III, R J Cantey, L L Steed, A A Estelle, H T Michels. Presented at the IPS Scottish Branch Conference 29 May 2014.

Poster presented on 29 May 2014 at the IPS Scottish Branch Conference 2014 - 'Get to Grips with SICPs' at Thistle Hotel, Glasgow, Scotland.


Surface Structure Influences Contact Killing of Bacteria by Copper
Marco Zeiger, Marc Solioz, Hervais Edongu, Eduard Arzt & Andreas S. Schneider. MicrobiologyOpen 2014; 3(3): 327–332.

Copper kills bacteria rapidly by a mechanism that is not yet fully resolved. The antibacterial property of copper has raised interest in its use in hospitals, in place of plastic or stainless steel. On the latter surfaces, bacteria can survive for days or even weeks. Copper surfaces could thus provide a powerful accessory measure to curb nosocomial infections. We here investigated the effect of the copper surface structure on the efficiency of contact killing of Escherichia coli, an aspect which so far has received very little attention. It was shown that electroplated copper surfaces killed bacteria more rapidly than either polished copper or native rolled copper. The release of ionic copper was also more rapid from electroplated copper compared to the other materials. Scanning electron microscopy revealed that the bacteria nudged into the grooves between the copper grains of deposited copper. The findings suggest that, in terms of contact killing, more efficient copper surfaces can be engineered.

epic3: National Evidence-Based Guidelines for Preventing Healthcare-Associated Infections in NHS Hospitals in England
H P Loveday, J A Wilson, R J Pratt, M Golsorkhi, A Tingle, A Baka, J Browne, J Prieto, M Wilcox. Journal of Hospital Infection 86S1 (2014) S1–S70

National evidence-based guidelines for preventing healthcare-associated infections (HCAI) in National Health Service (NHS) hospitals in England were originally commissioned by the Department of Health and developed during 1998-2000 by a nurse-led multi-professional team of researchers and specialist clinicians. Following extensive consultation, they were  first published in January 2001 and updated in 2007. A cardinal feature of evidence-based guidelines is that they are subject to timely review in order that new research evidence and technological advances can be identified, appraised and, if shown to be effective for the prevention of HCAI, incorporated into amended guidelines.Periodically updating the evidence base and guideline recommendations is essential in order to maintain their validity and authority.

The Department of Health commissioned a review of new evidence and we have updated the evidence base for making infection prevention and control recommendations. A critical assessment of the updated evidence indicated that the epic2 guidelines published in 2007 remain robust, relevant and appropriate, but some guideline recommendations required adjustments to enhance clarity and a number of new recommendations were required. These have been clearly identified in the text.  In addition, the synopses of evidence underpinning the guideline recommendations have been updated.

These guidelines (epic3) provide comprehensive recommendations for preventing HCAI in hospital and other acute care settings based on the best currently available evidence. National evidence-based guidelines are broad principles of best practice that need to be integrated into local practice guidelines and audited to reduce variation in practice and maintain patient safety. Clinically effective infection prevention and control practice is an essential feature of patient protection. By incorporating these guidelines into routine daily clinical practice, patient safety can be enhanced and the risk of patients acquiring an infection during episodes of health care in NHS hospitals in England can be minimised.

See Section 2.2, Hospital Environmental Hygiene, under Emerging Technology.

Understanding the Role of Facility Design in the Acquisition and Prevention of Healthcare-associated Infections
Health Environments and Research Design Journal, Vol 7, Supplement, 2013

This special issue focuses on healthcare-associated infections and is sponsored by the Agency for Healthcare Research and Quality (AHRQ), part of the US Department of Health and Human Services. The majority of articles are the result of a project sponsored by the AHRQ. The project was designed to assess the rigor of claims asserting that design interventions can decrease infection risk, and to identify design strategies grounded in evidence that appear to be effective in interrupting the transmission of HAIs. This project represents a multidisciplinary assessment of the current state of knowledge and identifies emerging trends in the field of infection prevention within the context of the built environment.  Copper touch surfaces are mentioned in several articles (p31, p46 and p127).

Inactivation of Norovirus on Dry Copper Alloy Surfaces
Warnes SL, Keevil CW (2013)

Noroviruses (family Caliciviridae) are the primary cause of viral gastroenteritis worldwide. The virus is highly infectious and touching contaminated surfaces can contribute to infection spread. Although the virus was identified over 40 years ago the lack of methods to assess infectivity has hampered the study of the human pathogen. Recently the murine virus, MNV-1, has successfully been used as a close surrogate. Copper alloys have previously been shown to be effective antimicrobial surfaces against a range of bacteria and fungi. We now report rapid inactivation of murine norovirus on alloys, containing over 60% copper, at room temperature but no reduction of infectivity on stainless steel dry surfaces in simulated wet fomite and dry touch contamination. The rate of inactivation was initially very rapid and proportional to copper content of alloy tested. Viral inactivation was not as rapid on brass as previously observed for bacteria but copper-nickel alloy was very effective. The use of chelators and quenchers of reactive oxygen species (ROS) determined that Cu(II) and especially Cu(I) ions are still the primary effectors of toxicity but quenching superoxide and hydroxyl radicals did not confer protection. This suggests Fenton generation of ROS is not important for the inactivation mechanism. One of the targets of copper toxicity was the viral genome and a reduced copy number of the gene for a viral encoded protein, VPg (viral-protein-genome-linked), which is essential for infectivity, was observed following contact with copper and brass dry surfaces. The use of antimicrobial surfaces containing copper in high risk closed environments such as cruise ships and care facilities could help to reduce the spread of this highly infectious and costly pathogen.

Evaluation of new In Vitro efficacy test for antimicrobial surface activity reflecting UK hospital conditions
M Ojeila, C Jermannb, J Holahb, S P Denyera, J-Y Maillard

The aim of this study was to develop a new antimicrobial surface test to replace the JISZ2801 that evaluates the activity of antimicrobial surfaces under parameters reflective of conditions in healthcare settings.

Financial Benefits after the Implementation of Antimicrobial Copper in Intensive Care Units (ICUs)
P Efstathiou, E Kouskouni, S Papanikolaou, K Karageorgou, Z Manolidou, M Tseroni, E Logothetis, C Petropoulou, V Karyoti. Antimicrobial Resistance and Infection Control 2013, 2(Suppl 1):P369

Meeting extract - Antimicrobial Resistance and Infection Control, 2nd International Conference on Prevention and Infection Control (ICPIC 2013), Geneva, Switzerland, 25-28 June 2013.

Objectives: Aim of this study was to evaluate the reduction on Intensive Care Unit (ICU) microbial flora after the antimicrobial copper alloy (Cu+) implementation as well as the effect on financial - epidemiological operation parameters.

Methods: Medical, epidemiological and financial data into two time periods, before and after the implmentation of copper (Cu 63% - Zn 37%, Low Lead) were recorded and analysed in a General ICU.  The evaluated parameters were: the importance of patients' admission (Acute Physiology and Chronic Health Evaluation - APACHE II and Simplied Acute Physiology Score - SAPS), microbial flora's record in the ICU before and after the implementation of Cu+, as well as the impact on epidemiological and ICU's operation financial parameters.

Results: During December 2010 and March 2011, and respectively during December 2011 and March 2012, comparative results showed statistically significant reduction on the microbial flora (CFU / ml) by 95% and the use of antimicrobial medicine (per day per patient) by 30% (p=0,014), as well as patients' hospitalisation time and cost.

Conclusion: The innovative implementation of antimicrobial copper in ICUs contributed to their microbial flora significant reduction and antimicrobial drugs use reduction with the apparent positive effect (decrease) in both patients' hospitalisation time and cost.  Under the present circumstances of economic crisis, survey results are of highest importance and value.

Disclosure of interest: None declared.

(Poster 369)

Implementation of Antimicrobial Copper in Neonatal Intensive Care Unit
P Efstathiou, M Anagnostakou, E Kouskouni, C Petropoulou, K Karageorgou, Z Manolidou, S Papanikolaou, M Tseroni, E Logothetis, V Karyoti. Antimicrobial Resistance and Infection Control 2013, 2(Suppl1):O68.

Meeting extract - Antimicrobial Resistance and Infection Control, 2nd International Conference on Prevention and Infection Control (ICPIC 2013), Geneva, Switzerland, 25-28 June 2013.

Objectives: The aim of this study was to investigate the effectiveness of the application of antimicrobial copper alloys (Cu+) in a Neonatal Intensive Care Unit (NICU) in relation to the reduction of microbial flora.

Methods: At a Level III Neonatal Intensive Care Unit of a paediatric hospital, with the capacity of 26 incubators, antimicrobial copper (Cu+) was implemented on touch surfaces and objects.  The copper alloy contains Cu 63% - Zn 37% (Lead Low).  Microbiological cultures were taken in three different time periods, before and after the application of Cu+, using dry and wet method technique.

Results: In the above NICU, the reduction of microbial flora after the implementation of the antimicrobial copper (Cu+) on the selected surfaces and objects was statistically significant (n=15, p<0,05) and was recorded at 90%.  The pathogens isolated at high rates (CFU / ml) prior to copper implementation were as follows: Klebsiella spp., Staph. Epidermidis, Staph.  Aureus, Enterococcus spp.

Conclusion: This study highlights the positive impact of antimicrobial copper (Cu+) and demonstrates that copper implemented surfaces and objects are effective in neutralising bacteria which are responsible for Healthcare Acquired Infections in the nosocomial environment (HCAIs).  The innovative implementation of antimicrobial copper in the NICU and the significant reduction of microbial flora heralds the reduction of antimicrobial drugs use, and a possible reduction of hospital acquired infections and hospitalisation time.

Disclosure of interest: None declared

(Poster 68)

The Economic Assessment of an Environmental Intervention: Discrete Deployment of Copper for Infection Control in ICUs
M Taylor, S Chaplin, York Health Economics Consortium, York, UK, Antimicrobial Resistance and Infection Control 2013, 2(Suppl1):P368

Meeting extract - Antimicrobial Resistance and Infection Control, 2nd International Conference on Prevention and Infection Control (ICPIC 2013), Geneva, Switzerland, 25-28 June 2013.

Introduction: Health Economics evaluations are typically applied to medications or surgery costs, but this unique study has investigated the economic benefits of discrete deployment of antimicrobial copper alloy touch surfaces in ICUs.

Copper/copper alloy surfaces have been shown to act as an adjunct to standard infection control practices in diverse clinical settings, continuously reducing contamination by over 90%.  Moreover, work reported by Dr Michael Schmidt at the first ICPIC revealed the link between reduced bioburden and significant reductions in the risk of acquiring an HCAI.

This study investigates the cost-effectiveness of this intervention, comparing expenditure with the improvements in patient outcomes and other tangible benefits.

Methods: Following an extensive literature review and use of expert opinion a number of factors have been considered in this evaluation, including component cost and longevity balanced with cost of care.  Despite a lack of robust comparable data on the cost of HCAIs available in the public domain, good references were identified and used to  calculate cost of care.  Commercial data is available for the cost of the intervention and has been used to predict a return on investment (ROI) for installing a set of copper components as part of a new build or planned refurbishment.  Consideration is also given to who in a hospital might specify such an intervention, where the budget resides and where cost savings could be realised.  A model has been created to show the economic impact of an environmental intervention.

Results: The model predicts the cost of replacing key, frequently-touched surfaces in a 20-bed UK ICU with copper equivalents will be recouped in less than two months.  Thereafter, ongoing cost savings will accrue from the reduction in blocked beds and better-directed staff resources.

Conclusion: The investigation allowed the derivation of a spreadsheet-based model that uses the best current published information and shows the rapid ROI of a copper intervention.  It also calculates the impact on bed days and quality-adjusted life years (QALY).  The model is simple, transparent to those with knowledge of spreadsheets, and allows adaptation to specific local settings.

Disclosure of interest: None declared.

(Poster 368)

Copper Surfaces Reduce the Rate of Healthcare-Acquired Infections in the Intensive Care Unit
Cassandra D Salgado, MD; Kent A Sepkowitz, MD; Joseph F John, MD; J Robert Cantey, MD; Hubert H Attaway, MS; Katherine D Freeman, DrPH; Peter A Sharpe, MBA; Harold T Michels, PhD; Michael G Schmidt, PhD. Infection Control and Hospital Epidemiology

Objective: Healthcare-acquired infections (HAIs) cause substantial patient morbidity and mortality. Items in the environment harbour microorganisms that may contribute to HAIs. Reduction in surface bioburden may be an effective strategy to reduce HAIs. The inherent biocidal properties of copper surfaces offer a theoretical advantage to conventional cleaning, as the effect is continuous rather than episodic.  We sought to determine whether placement of copper alloy-surfaced objects in an intensive care unit (ICU) reduced the risk of HAI.

Design: Intention-to-treat randomised control trial between 12 July 2010 and 14 June 2011.

Setting: The ICUs of 3 hospitals.

Patients: Patients presenting for admission to the ICU.

Methods: Patients were randomly placed in available rooms with or without copper alloy surfaces, and the rates of incident HAI and/or colonisation with methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant Enterococcus (VRE) in each type of room were compared.

Results: The rate of HAI and/or MRSA or VRE colonization in ICU rooms with copper alloy surfaces was significantly lower than that in standard ICU rooms (0.071 vs 0.123). For HAI only, Pp.020 the rate was reduced from 0.081 to 0.034 (Pp.013).

Conclusions: Patients cared for in ICU rooms with copper alloy surfaces had a significantly lower rate of incident HAI and/or colonisation with MRSA or VRE than did patients treated in standard rooms.  Additional studies are needed to determine the clinical effect of copper alloy surfaces in additional patient populations and settings.

Infection Control and Hospital Epidemiology , Vol. 34, No. 5, Special Topic Issue: The Role of the Environment in Infection Prevention (May 2013), pp. 479-486.

Copper Continuously Limits the Concentration of Bacteria Resident on Bed Rails within the Intensive Care Unit
Michael G Schmidt, PhD; Hubert H Attaway III, MS; Sarah E Fairey, BS; Lisa L Steed, PhD; Harold T Michels, PhD; Cassandra D Salgado, MD, MS Infection Control and Hospital Epidemiology, Vol. 34, No. 5.

Cleaning is an effective way to lower the bacterial burden (BB) on surfaces and minimize the infection risk to patients. However, BB can quickly return.  Copper, when used to surface hospital bed rails, was found to consistently limit surface BB before and after cleaning through its continuous antimicrobial activity.

Special Topic Issue: The Role of the Environment in Infection Prevention (May 2013), pp. 530-533.

Contact Killing of Bacteria on Copper is Suppressed if Bacterial-Metal Contact is Prevented and Induced on Iron by Copper Ions
Salima Mathews, Michael Hans, Frank Mücklich, Marc Solioz, Applied and Environmental Microbiology, April 2013, Vol 79, No 8. Copyright © American Society for Microbiology. doi:10.1128/AEM.03608-12.

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 4mM 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.

Antimicrobial activity of copper surfaces against carbapenemase-producing contemporary Gram-negative clinical isolates
Souli M, Galani I, Plachouras D, Panagea T, Armaganidis A, Petrikkos G, Giamarellou H.

The antimicrobial activity of copper surfaces against a variety of contemporary carbapenemase-producing Gram-negative bacteria representative of the most problematic nosocomial pathogens worldwide was evaluated.

It was concluded that copper has significant antimicrobial activity against multidrug-resistant nosocomial Gram-negative pathogens. This supports the hypothesis that replacement of high-contact materials with copper could reduce the high burden of environmental contamination around high-risk patients. However, this strategy should be seen as an adjunctive measure to established cleaning protocols and to good hygiene practices for prevention of hospital-acquired infections.

4th Department of Internal Medicine, Athens University School of Medicine, University General Hospital 'Attikon', 1 Rimini Str. 124 62, Chaidari, Athens, Greece. J Antimicrob Chemother. 2012 Dec 9. [Epub ahead of print].

Experimental Tests of Copper Components in Ventilation Systems for Microbial Control
Charles Feigley, Jamil Khan, Deborah Salzberg, James Hussey, Hubert Attaway, Lisa Steed, Michael Schmidt and Harold Michels, (2013), HVAC&R Research, 19:1, 53-62

Colonization of HVAC systems by microbes may lead to release of hazardous bioaerosols containing allergens, irritants, odorants or infectious agents to outdoor air, possibly adversely affecting system performance.  Unlike the many common materials used in HVAC systems, copper and copper alloys have ben shown in laboratory investigations to kill bacteria and fungi on contact after several hours.  This study tested copper's antimicrobial properties in comparison with aluminium in full-scale, carefully controlled air-conditioning systems, four with copper heat exchanger facilities and four with aluminium assemblies, at identical airflow rates, temperatures, humidity, and input microbe levels.  Fungal and bacterial loads on copper surfaces in heat exchangers were lower than on aluminium surfaces by factors of 3500 and more than 500, respectively, over a 4-month period.  No statistically significant difference in the release of airborne microbes was detected between copper and aluminium heat exchangers.  The moderate conditions employed in this study, while still within the range commonly found in HVAC systems, possibly prevented the high microbial loading on aluminium heat exchanger surfaces from translating into significant differences in airborne concentrations betweeen copper and aluminium systems.

Horizontal Transfer of Antibiotic Resistance Genes on Abiotic Touch Surfaces: Implications for Public Health
Sarah L. Warnes, Callum J Highmore, and C William Keevil, Centre for Biological Sciences, University of Southampton, Highfield Campus, Southampton, UK. doi: 10.1128/​mBio.00489-12 27 November 2012 mBio vol. 3 no. 6 e00489-12

Horizontal gene transfer (HGT) is largely responsible for increasing the incidence of antibiotic-resistant infections worldwide. While studies have focused on HGT in vivo, this work investigates whether the ability of pathogens to persist in the environment, particularly on touch surfaces, may also play an important role.

Antimicrobial Effect of Copper on Multidrug-resistant Bacteria
G. Steindl, S. Heuberger and B. Springer. Wiener Tierärztliche Monatsschrift – Veterinary Medicine Austria 99 (2012).

Copper has been used for centuries as a therapeutic agent in various cultures around the globe. With the emergence and spread of antibiotic resistance, the use of metallic copper alloys to control pathogenic microorganisms is attracting increasing attention. We investigated the antimicrobial effect of copper on three multidrug-resistant bacterial strains: methicillin-resistant  Staphylococcus aureus sequence type 398, CTX-M-15 producing  Escherichia coli and NDM-1 producing Klebsiella pneumoniae.

Copper coupons were inoculated with bacterial cell suspensions and incubated at room temperature. At set time points, bacteria were resuspended and plated onto nutrient agar and colony-forming units were counted. Results show a more than fivefold log-reduction of viable bacteria for CTX-M-15 producing  E. coli and NDM-1 producing  K. pneumoniae after 60 min of incubation on metallic copper compared to stainless steel. The same reduction of viable bacteria could be demonstrated for methicillin-resistant S. aureus sequence type 398 after 120 min of incubation.

Our data complement scientific evidence for copper´s antimicrobial properties on multidrug-resistant bacteria and suggest that the use of copper surfaces constitutes an approach to support the control of these organisms.

Miedź i jej stopy są materiałami inżynierskimi o dużej wytrzymałości, bogatej kolorystyce, nadającymi się do ponownego przetwarzania. Metale te są ogólnie dostępne w postaci całej gamy półproduktów przeznaczonych do produkcji różnorodnych wyrobów gotowych. Miedź i jej stopy stanowią atrakcyjny zestaw materiałów dla projektantów tworzących funkcjonalne, ekologiczne i przystępne cenowo produkty.

Czysta miedź oraz niektóre jej stopy (określane wspólnym mianem Miedzi Przeciwdrobnoustrojowej) posiadają naturalne właściwości przeciwdrobnoustrojowe, a produkty z nich wykonane zyskują dodatkową funkcję, nie związaną z ich pierwotnym przeznaczeniem - służą podniesieniu poziomu higieny. Wyroby z Miedzi Przeciwdrobnoustrojowej stanowią uzupełnienie, a nie substytut standardowych praktyk kontroli zakażeń. Niezbędne jest przestrzeganie istniejących procedur w zakresie utrzymania higieny, włączając w to procedury czyszczenia i dezynfekcji powierzchni zmywalnych.

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