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Clinical trials of antimicrobial copper alloy touch surfaces in healthcare facilities
In hospitals, hand and surface disinfection practices are the first line of defense against infection. However, these have fallen short of expectations as opportunistic organisms put patients and healthcare workers at risk. Since approximately 80% of infectious diseases are known to be transmitted by touch, and pathogens found in healthcare facilities can survive on inanimate surfaces for days and even months, the microbial burden of frequently touched surfaces is believed to play a significant role in infection causality. Surfaces in hospitals and healthcare facilities are frequently touched and could therefore could become reservoirs of infection. These include door handles, push plates, light switches, bed rails, grab rails, intravenous poles, dispensers (alcohol gel, paper towel, soap), dressing trolleys, and counter and table tops.

Recently, to evaluate their effectiveness as a secondary infection control measures, these products have been made from copper and its alloys and deployed in hospital geriatric wards, intensive care units, and general medical wards around the world.

Clinical trials are being conducted on microbial strains unique to individual healthcare facilities around the world to evaluate to what extent copper alloys can reduce the incidence of infection in hospital environments.

The success of these clinical trials to date, which are summarized here, are prompting hospitals around the world to specify antimicrobial copper touch surfaces as an additional weapon in the fight against infection.

Clinical trial in the United Kingdom
In the United Kingdom, around 300,000 patients contract nosocomial infections each year and at least 5,000 patients die of complications from infections contracted in hospitals.

For these reasons, a cross-over clinical trial (a test method designed to eliminate variability bias from patients, staff, cleaning efficacy, outbreaks, etc.) evaluating antimicrobial copper alloys was carried out at Selly Oak Hospital over an 18-month period in 2007-2008 by the University Hospital Birmingham NHS Trust and Aston University.

Frequently touched surfaces typically manufactured with standard materials (i.e., plastic, chrome, aluminum) were replaced with copper alloys. These included a copper alloy toilet seat (impregnated organic coating, approximately 70% Cu), a set of sink tap handles (60% Cu, 40% Zn), and a ward entrance door push plate (70% Cu, 30% Zn).

Contamination reductions of 90-100% were observed for Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumanii, Enterococcus spp., and Candida albicans on the copper alloy surfaces versus the non-copper standard surfaces. A microorganism reduction of 100% was observed on the hot tap copper alloy handle.

The high degree of clinical performance suggested that copper alloy surfaces may increase the effectiveness of existing infection control practices and may lower the risk of infections acquired in healthcare facilities.

Based on the results of this and other laboratory and clinical studies, St. Francis Private Hospital, a 140-bed facility located in Mullingar, County Westmeath, Ireland, decided to reduce healthcare associated infections by becoming the first hospital in the world to fully specify hygienic copper door handles throughout its facility. A full upgrade of all door furniture (i.e., 250 doorsets, incorporating handles, push plates and privacy locks) to antimicrobial copper in the hospital and nursing home commenced in January 2010.

Healthcare architects in the United Kingdom are now specifying antimicrobial copper. Refurbishment projects specifying copper products are anticipated across NHS Trust facilities.

Clinical trial in Chile
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). Nine hundred ninety 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-the-bed tables were made from copper alloy C70600. Bedrails were cladded 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 study.

Copper was effective in reducing microbial loads on all 6 surfaces tested (i.e., bed rails by 91%, bed levers by 82%, tray tables by 83%, chair arms by 92%, monitor pen by 49%, and IV poles by 88%).

Average microbial burden counts in rooms with copper touch surfaces were significantly lower than in rooms without copper surfaces. Staphylococci were the most predominant microorganism isolated and copper was effective in reducing the Staphylococci microbial burden. Further studies regarding the clinical implications of copper’s intrinsic ability to reduce microbial burdens in hospitals are being planned.

Clinical trials in Japan
Researchers from the Kitasato University School of Medicine conducted antimicrobial studies of S. aureus, E. coli, and P. aeruginosa on various Japanese copper alloy coins and on copper alloy plates. The microbes were strains from hospital environments. Copper and its nickel-silver, cupronickel, and brass alloys were found to kill the bacteria within a short time. In another experiment, bacterial colonies were investigated on ball point pens made with and without copper alloys. Total bacterial colonies on the copper pens were much lower than on the non-copper pens: 2.1 CFU versus 47.8 CFU. Staphyloccocus counts on copper ball point pens were also much lower: 0.7 CFUs versus 20.8 CFUs on non-copper pens.

Due to these success of these results, a 2-year clinical trial was conducted to monitor contamination levels of nosocomial bacteria in the dermatology ward and neonatal intensive care unit (NICU) at Kitasato University Hospital. The antimicrobial efficacy of copper on floors, sinks, push plates, showerheads and doorknobs was evaluated by comparing bacterial loads on these surfaces and on their non-copper counterparts.

The number of viable Staphylococcus spp. organisms on surfaces containing copper and its alloy were reduced by half to one-thirtieth of that on control surfaces, depending upon surface humidity and the frequency of contact. Similar definitive findings were also obtained for Pseudomonas aeruginosa.

Various metals were evaluated for their antimicrobial efficacies, including copper alloys, zinc, nickel, tin, silver, and gold. Antimicrobial efficacies generally followed Lewis acidity values of the various metals. Silver, a prohibitively expensive precious metal, had the highest bactericidal activity; copper came in second. The study also found that contact dermatitis allergies rarely occur if copper is used as a hygienic touch material.

A copper coated-film (copper coating on a plastic surface) also reduced the bioburden on sheets used by patients infected with MRSA and P. aeruginosa.

The bactericidal activity of copper was also tested against two strains of MRSA and S. aureus in vitro to determine whether copper alloys are effective in preventing the spread of contamination on the touch surface products used in the hospital ward. MRSA and S. aureus counts fell below detection limits within 180 minutes. The results indicated that copper has a strong bactericidal effect against S. aureus, including MRSA.

When a copper plate was situated on a MRSA-infected floor in the dermatology ward around a bed of a MRSA-infected patient, the bacterial count of S. aureus, including MRSA and the other Staphylococcus on the floor covered with a copper plate was significantly less than on a floor unprotected by copper alloys. These results suggested that the copper plate helped to prevent the spread of MRSA contamination in the hospital.

Clinical Trial in South Africa
Multidrug-resistant and extremely drug resistant Mycobacterium tuberculosis (MTB) is responsible for the spread of tuberculosis in South African hospitals. A clinical study was conducted to establish the minimum in-vitro activity of copper and its alloys that would produce sterilization against MTB, as well as other highly resistant nosocomial pathogens and yeast isolated from South African patients. Test strains of Candida albicans, Pseudomonas aeruginosa, Klebsiella pneumoniae and meticillin-resistant Staphylococcus aureus (MRSA) were isolated from patients at a hospital’s intensive care unit. Acinetobacter baumannii was isolated from a patient in a burn unit and two clinical strains of MTB were collected and tested.

Copper and its alloys demonstrated antimicrobial activities against multiple-antibiotic-resistant nosocomial bacteria and C. albicans isolated from the hospital, whereas stainless steel and PVC did not. Copper and its alloys showed a marked inhibitory effect (88-98%) on MTB despite the strain’s drug resistance. The researchers concluded that the minimum concentration of copper to be an effective antimicrobial agent is >55% for yeasts and bacteria. Higher concentrations of copper were found to be necessary to inhibit MTB.

Clinical trial in Germany
Health experts estimate that more than 500,000 hospital patients contract hospital-borne infections every year in Germany.

The Askelpios Klinik, in Hamburg, was chosen as a designated hospital facility for an antimicrobial copper alloy clinical trial. The hospital is a member of one of the largest hospital chains in the world which manages 100 institutions and treats over 1 million patients each year. Aluminum door handles and plastic light switches in several rooms of the geriatric ward and adjacent bathrooms were replaced with copper alloy light switch plates and doorknobs. Researchers from the University of Halle-Wittenberg, Germany, collected samples daily for several months and compared the number of germs, including MRSA, on aluminum, stainless steel, plastic, and copper surfaces. The study found that germ loads on copper surfaces were 33% lower than on the alternate materials.

Clinical trials in the USA
In the USA, a high degree of statistical significance is needed to provide a convincing argument to U.S. federal government healthcare authorities, such as the Centers for Disease Control and Prevention (CDC), regarding the effectiveness of copper alloys in reducing microbial loads and cross infection in healthcare environments. For this reason, clinical trials at three major US hospitals are currently examining environmental bacterial loads, infection rates, and impacts on cross-contamination in intensive care unit (ICU) rooms retrofitted with copper touch surfaces versus rooms without copper surfaces.

The trials are funded by the U.S. Department of Defense (DOD) under the Telemedicine and Advanced Technologies Research Center (TATRC), a section of the United States Army Medical Research and Materiel Command (USAMRMC). DOD has extraordinary interests in the potential for antimicrobial copper surfaces to reduce hospital-acquired infections because it wants to prevent hospital-acquired infections among thousands of its enlisted armed forces servicemen and servicewomen who have been injured in recent conflicts. TATRC, which funds a Military Infectious Disease Program has been granted funds by the United States Congress to evaluate the antimicrobial effectiveness of copper, brass and bronze alloys. The studies are coordinated through the Advanced Technology Institute in Charleston, South Carolina.

The clinical studies involve 8 intensive care units (ICUs) at one of the world’s most prestigious cancer facilities, the Memorial Sloan-Kettering Cancer Center in New York City, as well as the Medical University of South Carolina, and the Ralph H. Johnson VA Medical Center in Charleston, South Carolina.

An evaluation of the microbial burden of various objects in the ICU rooms has been documented and is available. Results from the pilot study at the Medical University of South Carolina are summarized here (for more details, see: ). Two hundred eighty two copper objects in 32 rooms and 288 non-copper objects in 27 rooms were sampled. The study found that continuous antimicrobial activities of copper alloys are very effective in reducing total microbial burden in patient rooms and on individual objects within those rooms. Copper was effective in reducing the total mean microbial burden of patient ICU rooms by 87.4%. Copper was effective in reducing the microbial burden on bedrails, chair arms, nurse call buttons, and IV poles (though no significant reductions were observed on monitors and tray tables). It is important to note that significant reductions were observed when bed rails and call buttons were made from copper because these items accounted for 83.3% of the total mean MB in non-copper rooms. It is also important to note that MRSA and VRE were frequently isolated from non-copper rooms but were never isolated from copper objects. The copper alloys completely destroyed MRSA and VRE, microorganisms that are frequently responsible for potentially fatal patient infections. Details of the results of the clinical study are available.

Results from studies at the Memorial Sloan-Kettering Cancer Center and the Ralph H. Johnson VA Medical Center are in peer review and will be published shortly.

In a separate initiative not funded by the U.S. Department of Defense, clinical trials at an infectious disease outpatient ward consisting of patients with HIV and other infectious diseases are being conducted at North Shore University Hospital in Manhasset, New York. An alloy of 90% Cu 10% Ni significantly lowered the microbial burden, primarily Staphylococci, on arm surfaces of phlebotomy chairs versus wooden arm surfaces. The median reduction for total bacteria on the copper alloy chairs arms was 90%. Use of the chair with copper arm tops resulted in a 17-fold lower risk of exposure to environmental microbes than when patients used the standard chair. The majority of the samples from the chairs with copper components were below the 500 CFU/ cm2 level believed to represent a risk to hospital patients. The microbiocidal properties of the copper chair arms were able to confer an ‘antimicrobial halo’ within the general vicinity of the arm top. The microbial burden associated with the wooden side arms of the copper covered chair arms was 70%, lower than those on the control chair. This halo effect may help to help reduce the transfer of pathogenc bacteria.

Similarly, patients and healthcare workers who used chairs with copper trays were subjected to a 15-fold lower risk than the patients using chairs with composite trays. The microbial burden on copper trays was reduced by 88% compared to the composite plastic surface.

