A Copper Alliance Member
Studies Show Copper Surfaces May Help Thwart "Superbug" Hospital Infections, Says Copper Development Association
May 11, 2006
FOR IMMEDIATE RELEASE
A 2000-year history of the antimicrobial applications of copper metals has given rise to current efforts to determine their effectiveness in stemming infectious disease in healthcare and other public facilities.
Recent studies sponsored by the Copper Development Association Inc. (CDA) and the International Copper Association, Ltd., have shown that uncoated copper and copper alloys can inactivate the more virulent strains of antibiotic-resistant bacteria associated with hospital-acquired infections (HAI), such as Methicillin-resistant Staphylococcus aureus (MRSA) (Figure 1).
Figure 1. Methicillin-resistant Staphylococcus aureus (MRSA) bacteria thrive on stainless steel (blue) but die off quickly on copper (red) and brass (yellow) surfaces.High-resolution version of this photo.
The studies, conducted by Drs. William Keevil, Sandra Wilks and Jonathon Noyce at the University of Southampton, U.K., show that many common disease-causing microbes, including E. coli (Figures 2a and 2b ), Aspergillus niger (black mold) (Figure 3 ), and Influenza A, die within hours on copper surfaces.
Figure 2a . Epifluorescence Image after Staining with Fluorophore of E. coli on S30400 (stainless steel) after 90 Minutes at 20°C.High-resolution version of this photo.
Figure 2b . Epifluorescence Image after Staining with Fluorophore of E. coli on C10200 (copper) after 90 Minutes at 20°C.
According to Dr. Harold T. Michels, CDA’s vice president for technology and information services, MRSA was eliminated in laboratory studies on brass surfaces in 4.5 hours, and on pure copper in just 1.5 hours. Brass surfaces also inactivated the often deadly E. coli O157:H7 in less than two hours. On stainless steel and plastics, used for typical hospital and food-processing hardware, the pathogens can survive unabated for more than 30 days. Michels says it’s been shown that the higher the copper content of the alloy, the more quickly bacteria die.
Figure 3 . The Viability of Aspergillus niger on Surfaces of Aluminum, C24000 (brass) and C11000 (copper) at 20°C.High-resolution version of this photo.
CDA is about to conclude independent laboratory testing of five copper alloys on five different pathogens using U.S. Environmental Protection Agency prescribed protocols. These laboratory results will be presented to EPA this summer as part of the process to obtain registration for antimicrobial public health claims under the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA). If successful, copper will become the first and only solid material or coating to be granted a public health claim from EPA.
Touch Surfaces
Prescribed hygienic practices for sterilization of touch surfaces along with hand-washing are the first lines of defense but often go unheeded. The continuing rise in HAI suggests they are also inadequate. Adding to the problem is that there are few prospective antibiotics in the pipeline to combat evolving and resistant microbial strains — the superbugs. Consequently, medical, military and public communities are ill-prepared to protect patients and personnel. Meanwhile, little attention has been paid to the touch surfaces, themselves, that are a continual source of cross-contamination.
In healthcare facilities, surfaces in proximity to patients are of the most concern. Items such as door and furniture hardware (e.g., push plates, knobs, handles, drawer pulls), bed trays, bed rails, railings, IV stands, medical monitoring equipment, remote controls and keyboards, faucets, sinks, soap dispensers, countertops and other work surfaces are identified as the most critical to sanitize on a regular basis. Disinfectants and even antimicrobial coatings have finite efficacy, at best. Michels says Identifying and employing surface materials that can provide continual antimicrobial protection, accommodate the demands of everyday use, and require a minimum of maintenance would help stem infections induced by cross-contamination.
Clinical trials, now in development, seek to prove that use of copper metals for touch surfaces will provide a continual, proactive means to help reduce and/or preempt microbial pathogens in the healthcare environment. It is expected that by using copper alloys, together with a program of good hygienic practice, the need for antimicrobial drugs and the fostering of drug-resistant microbial strains will be significantly reduced and that infection rates will decline.
Bottom Line
“The challenge now,” says Michels, “is to engage health authorities, equipment manufacturers, regulators and other stakeholders in taking the next steps to continue their research and pursue product development using the most compatible copper alloys for appropriate applications.” This will require balancing the antimicrobial efficacy of copper alloys with other required attributes, such as formability, durability, ease of fabrication, aesthetic appeal, surface finishes, corrosion resistance, tarnish resistance and reactivity to foods, disinfectants and cleaning solutions. “By early next year, he says, we expect there will be a solid base upon which to put man’s oldest metal to work throughout the world to help protect us from infectious disease.”
Background
Before it was recognized that microorganisms existed, the Egyptians, Greeks, Romans and Aztecs used copper compounds for the treatment of disease and good hygiene. Egyptians used copper as a sterilization agent for drinking water and wounds. Hippocrates treated open wounds and skin irritations with copper. The Romans catalogued numerous medicinal uses for copper for various diseases. The Aztecs treated sore throats with copper, while in Persia and India copper was applied to treat boils, eye infections and venereal ulcers. In the 19 th century, after microbes were discovered and the germ theory of infection linked bacteria and other microorganisms to infection and disease, scientists began to understand how copper’s antimicrobial property could be harnessed to provide additional benefits. Today, the antimicrobial uses of copper have been expanded to include fungicides, antifouling paints, antimicrobial medicines, oral hygiene products, hygienic medical devices, antiseptics and a host of other useful applications.
###
The Copper Development Association is the information, education, market and technical development arm of the copper, brass and bronze industries in the USA.
Learn more at our blog coppertalk.org.
Follow us on Twitter at twitter.com/coppertalk.
