Clinical trials investigating Antimicrobial Copper's potential to help fight pathogens that cause healthcare-associated infections are providing proof of efficacy in challenging clinical environments around the world.
Laboratory testing has demonstrated conclusively that Antimicrobial Copper continuously kills bacteria that cause infections and is the most effective touch surface. Now, clinical trials under way around the world are demonstrating the benefit of Antimicrobial Copper in actual use conditions. These have taken/are taking place in many hospital settings around the world, providing a variety of trial protocols, ward types (geriatric, intensive care and general medical), local clinical strains of organisms and national healthcare environments to put Antimicrobial Copper to the test.
Results show that microbial contamination is significantly and consistently reduced on copper compared to standard surfaces, by 83-100%.
Results from a US clinical trial, funded by the Department of Defense, take this evidence to a new level by evaluating the connection between contamination on frequently touched surfaces and patient acquisition of infections. The published findings1 demonstrate that the use of antimicrobial copper surfaces in intensive care units (ICUs) can reduce the number of healthcare-associated infections (HCAIs) by 58% as compared to patients treated in ICUs with non-copper touch surfaces.
This is the first time an intervention designed to reduce microbial burden has had a clinical impact on ICU patients.
A translational science article2 discusses copper alloys as antimicrobial environmental surfaces, telling the story from laboratory testing, EPA registration and the US clinical trial.
An overview of the different clinical trials is presented below.
Three medical centres - The Medical University of South Carolina, Charleston (MUSC), The Ralph H Johnson Veterans Administration Medical Center, Charleston, South Carolina and the Memorial Sloan Kettering Cancer Center in New York City - participated in a clinical trial assessing copper's antimicrobial efficacy in intensive care units (ICUs). The institutions replaced stainless steel, aluminium and plastic touch surfaces with antimicrobial copper alloys, hereafter referred to as 'copper', on the following frequently-touched objects within selected rooms in each of the ICUs: bed rails, overbed tray tables, chairs, call buttons, data devices and IV poles.
The surfaces shown to be most contaminated and, not surprisingly, in closest proximity to patients and visitors, were replaced with copper components. No changes were made to clinical practices or cleaning regimes in the study rooms.
The trial was conducted by infectious disease clinicians and led by Dr Michael Schmidt, Professor and Vice Chair of the Microbiology and Immunology Department at MUSC.
The microbial burden (MB) associated with commonly touched surfaces in ICUs was determined by sampling six objects in 16 rooms in ICUs in three hospitals over 43 months3 .
At month 23, copper-alloy surfaces, with inherent antimicrobial properties, were installed onto six monitored objects in 8 of 16 rooms, and the effect that this application had on the intrinsic MB present on the six objects was assessed. Census continued in rooms with and without copper for an additional 21 months.
In concert with routine infection control practices, the average MB found for the six objects assessed in the clinical environment during the preintervention phase was 28 times higher (6,985 CFU/100 cm2; n = 3,977 objects sampled) than levels proposed as benign immediately after terminal cleaning (<250 CFU/100 cm2).
During the intervention phase, the MB was found to be significantly lower for both the control and copper-surfaced objects. Copper was found to cause a significant (83%) reduction in the average MB found on the objects (465 CFU/100 cm2; n = 2714 objects) compared to the controls (2,674 CFU/100 cm2; n = 2,831 objects [P < 0.0001]).
The introduction of copper surfaces to objects formerly covered with plastic, wood, stainless steel, and other materials found in the patient care environment significantly reduced the overall MB on a continuous basis, thereby providing a potentially safer environment for hospital patients, health care workers, and visitors.
In the same trial, recontamination of copper and plastic bed rails was compared. Copper, when used to surface hospital bed rails, was found to consistently limit surface bioburden before and after cleaning through its continuous antimicrobial activity 4.
The results suggest that replacement of key frequently-touched surfaces with copper components reduces microbial burden, which results in a significant and consistent reduction in infection rates:
- Copper reduces the average number of microbes by 83%.
- Based on the total number of microbes measured for each of the surfaces sampled, the combined MRSA and VRE burdens were 96.8% lower on copper surfaces than on comparable plastic, wood, metal, and painted surfaces and were 98.8% lower on the bed rails, the most heavily burdened object.
- Copper surfaces have been found to substantially diminish the density of bacteria to levels below those considered a risk to patients for the acquisition of an infection.
- Microbial burden reduction on copper surfaces continuously achieves the same levels as terminal cleaning.
- The deployment of copper surfaces in ICUs led to a 58% reduction in infection rates.
- Copper's antimicrobial activity is continuous - it works non-stop and around the clock.
In a separate US outpatient study, not only was the reduction in microbial bioburden confirmed but a halo effect was observed - reduced contamination in the vicinity of the copper surfaces. The copper surfaces were shown to reduce the risk of exposure to environmental microbes by 17%5.
In the UK, Professor Tom Elliott, Consultant Microbiologist and Deputy Medical Director at University Hospitals Birmingham NHS Foundation Trust, led a trial at Selly Oak Hospital, Birmingham. The trial took place on a general medical ward fitted with both copper and standard components. It aimed to demonstrate copper's ability to reduce environmental contamination and improve patient outcomes as part of a 'care bundle' - a package of measures to fight infection.
The first results from the trial, following sampling of three products - taps, push plates and toilet seats - were presented at the Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) in Washington DC, USA, in October 2008. These results show that surfaces made from materials that contain copper kill a wide range of potentially harmful micro-organisms, significantly reducing the number of these organisms that can come into contact with patients, visitors and staff. Data from the three products sampled over a ten-week period showed that items made from copper had 90 - 100% fewer micro-organisms on them, compared with the same items made from standard materials (chrome-plated brass, aluminium and plastic)6.
Professor Elliott explains: "What this must mean is that the risk of picking up an infection is reduced, because we know that one of the vehicles where organisms can spread from one surface to another is by touching them. So the results are very exciting.
"The findings of a 90 to 100% killing of those organisms, even after a busy day on a medical ward with items being touched by numerous people, is remarkable. So it may well offer us another mechanism for trying to defeat the spread of infection."
The copper products installed for the clinical trial - door furniture, bathroom fittings, trolleys and overbed tables, have all been subject to the standard NHS cleaning protocols and formulations, including toilet and spillage cleaning. During the 24-36 months after installation, only some mild surface oxidation has taken place. With their copper, gold and bronze colours, the copper components appear markedly different to the standard components but were widely accepted by staff, patients and visitors.
The second phase of the trial involved sampling of the full range of copper and control surfaces over a period of 6 months to gather more data. Results reinforce the earlier findings, showing significantly lower levels of contamination on the copper surfaces compared to controls7.
In Chile, 70,000 nosocomial infections are reported each year, most commonly from common hospital-borne pathogens such as S. aureus, P aeruginosa and A. baumanii.
In a 30-week clinical trial at the Hospital del Cobre, in Calama, extensive microbial analyses were implemented at the facility's intensive care unit (ICU). 990 copper surfaces from 90 rooms containing 6 different copper objects were studied against an equivalent number of rooms and surfaces containing non-copper objects. Over-bed tables were made from copper alloy C70600. Bed rails were clad with copper alloy C11000 foils. Visitor chairs were fitted with copper alloy C70600 armrests. Copper alloy C71000 intravenous poles were provided. Writing pens used to input data on a touch screen were made from brass (70% Cu, 30% Zn).
Results of this clinical trial demonstrated an approximately 90% reduction of microorganisms on the copper items compared to the controls after ten weeks. A reduction in the total microbial burden was seen for each class of microbe evaluated. Furthermore, continuous antimicrobial activity of copper persisted throughout the study8.
Copper was effective in reducing microbial loads on all 6 surfaces tested (ie bed rails by 91%, bed levers by 82%, tray tables by 83%, chair arms by 92%, monitor pens by 49% and IV poles by 88%).
Average microbial burden counts in rooms with copper touch surfaces were significantly lower than rooms without copper surfaces. Staphylococci were the most predominant microorganism isolated and copper was effective in reducing the Staphylococci microbial burden.
In the Asklepios Clinic, Wandsbek, in Hamburg, Germany, aluminium door handles and plastic light switches in a geriatric ward and its adjacent bathrooms have been replaced by copper alloy equivalents. The patients in the control and trial wards have similar profiles. The results to date show a significant reduction in contamination on the copper components 9.
A trial conducted at a nursing home, in conjunction with the Helsinki University Department of Public Health, compared contamination on copper vs standard items in patient rooms, bathrooms and communal areas. Copper components included dressing trolleys, door handles, grab rails, handrails, shower drains and push buttons. The first results show higher levels of contamination on the non-copper items and presence of faecal and urinary bacteria, (Staphylococcus aureus, E. coli and Candida albicans) only on stainless steel, plastic and chromium components. On copper and copper alloy surfaces, only Gram-positive bacilli and cocci and normal environmental and skin flora were found.
Further trials are also under way in France, Spain, South Africa10, Greece and Japan.
Copper and copper alloys are engineering materials that are durable, colourful and recyclable and are widely available in various product forms suitable for a range of manufacturing purposes. Copper and its alloys offer a suite of materials for designers of functional, sustainable and cost-effective products.
Copper and certain copper alloys have intrinsic antimicrobial properties (so-called ‘Antimicrobial Copper’) and products made from these materials have an additional, secondary benefit of contributing to hygienic design. Products made from Antimicrobial Copper are a supplement to, not a substitute for standard infection control practices. It is essential that current hygiene practices are continued, including those related to the cleaning and disinfection of environmental surfaces.
- 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 , Vol. 34, No. 5, Special Topic Issue: The Role of the Environment in Infection Prevention (May 2013), pp. 479-486.
- From Laboratory Research to a Clinical Trial: Copper Alloy Surfaces Kill Bacteria and Reduce Hospital-Acquired Infections. Michels, H.T. 2015. Health Environments Research & Design Journal. 1–16.
- Sustained Reduction of Microbial Burden on Common Hospital Surfaces through Introduction of Copper. Michael G Schmidt, Hubert H Attaway, Peter A Sharpe, Joseph John Jr, Kent A Sepkowitz, Andrew Morgan, Sarah E Fairey, Susan Singh, Lisa L Steed, J Robert Cantey, Katherine D Freeman, Harold T Michels and Cassandra D Salgado. J Clin Microbiol July 2012 vol. 50 no. 7 2217-2223. Published ahead of print 2 May 2012, doi: 10.1128/JCM.01032-12.
- 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, Special Topic Issue: The Role of the Environment in Infection Prevention (May 2013), pp. 530-533.
- Evaluation of Antimicrobial Properties of Copper Surfaces in an Outpatient Infectious Disease Practice. Seema Rai, Bruce E Hirsch, Hubert H Attaway, Richard Nadan, S Fairey, J Hardy, G Miller, Donna Armellino, Wilton R Moran, Peter Sharpe, Adam Estelle, J H Michel, Harold T Michels and Michael G Schmidt.
- Role of Copper in Reducing Hospital Environment Contamination. A L Casey, D Adams, T J Karpanen, P A Lambert, B D Cookson, P Nightingale, L Miruszenko, R Shillam, P Christian and T S J Elliott, J Hosp Infect (2009), doi:10.1016/j.jhin.2009.08.018.
- The Antimicrobial Efficacy of Copper Alloy Furnishing in the Clinical Environment; a Cross-over Study. T J Karpanen, A L Casey, P A Lambert, B D Cookson, P Nightingale, L Miruszenko L and T S J Elliott. Infection Control and Hospital Epidemiology. 2012 Jan;33(1):3-9. doi: 10.1086/663644. Epub 2011 Dec 7.
- Effectiveness of Copper Contact Surfaces in Reducing the Microbial Burden (MB) in the Intensive Care Unit (ICU) of Hospital del Cobre, Calama, Chile. V Prado, C Durán, M Crestto, A Gutierrez, P Sapiain, G Flores, H Fabres, C Tardito, M Schmidt. Poster 56.044, presented at the 14th International Conference on Infectious Diseases, Miami, March 11, 2010.
- Survival of Bacteria on Metallic Copper Surfaces in a Hospital Trial. André Mikolay, Susanne Huggett, Ladji Tikana, Gregor Grass, Jörg Braun and Dietrich H Nies. Applied Microbial and Cell Physiology, DOI 10.1007/s00253-010-2640-1. May 2010.
- Antimicrobial Efficacy of Copper Touch Surfaces in Reducing Environmental bioburden in a South African Community Healthcare Facility. F Marais, S Mehtar and L Chalkley, J Hosp Infect (2009), doi:10.1016/j.jhin.2009.07.010.