2000-year history of the antimicrobial applications of copper

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(Figure 1.) Methicillin-resistant Staphylococcus aureus (MRSA)

bacteria thrive on stainless steel (blue) but die off quickly on

copper (red) and copper alloy surfaces. (Graphic: Business Wire)

5/11/2006 5:08:00 PM EST

BIOWIRE

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).

The studies, conducted by Drs. Keevil, Wilks and

Jonathon Noyce at the University of Southampton, U.K., show that

many common disease-causing microbes, including E. coli Aspergillus

niger (black mold) and Influenza A, die within hours on copper

surfaces.

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.

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

19th 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.

Note to Editors: Additional images are available for download from

the CDA Website at:

http://www.copper.org/about/pressreleases/homepage.html.

CONTACT:

For The Copper Development Association Ken Geremia, 212-251-7209

kgeremia@... or Harold Michels, 212-251-7224