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Researchers theorize that copper’s killing power is related to its conductivity: It may ‘short-circuit’ bugs, which would be beneficial in a hospital ICU.
Researchers theorize that copper’s killing power is related to its conductivity: It may ‘short-circuit’ bugs, which would be beneficial in a hospital ICU.

Copper surfaces can kill hospital microbes, study finds Add to ...

Most people check into a hospital with the hope of getting better. However, many patients pick up serious infections during their stay in the health-care system. Despite fastidious cleaning and the routine use of gloves by staff, the number of hospital-acquired infections in Canada has swelled to an estimated 250,000 cases a year, resulting in 8,000 to 12,000 deaths. Other developed countries are facing a similar threat to patient safety.

But U.S. researchers now think they have hit upon a relatively easy way to overcome this serious problem - cover frequently-touched surfaces with copper. Bacteria and viruses can't survive for very long on the metal, thereby reducing the risk of harmful bugs spreading from one person to another.

"It is a simple, elegant solution," said Michael Schmidt, a professor at the Medical University of South Carolina.

Dr. Schmidt led a pilot study in which copper was used instead of stainless steel and plastic in a wide range of objects in the intensive-care units of three U.S. hospitals. Copper covered the bed rails, tray tables, call buttons, IV poles and chair arms.

When the researchers took culture swabs from the copper surfaces, they found the level of microbes had "dropped well below what is considered to be a risk," Dr. Schmidt said. "And it doesn't need any intervention other than normal cleaning." The findings were presented at a recent medical conference in Atlanta.

Previous lab studies have shown that copper and copper alloys, such as brass and bronze, kill 99.9 per cent of bacteria within two hours.

Scientist aren't sure why copper has such powerful anti-microbial properties. But Dr. Schmidt suspects that copper's killing power is related to the fact that the metal is a tremendous conductor of electricity. "What I think is probably happening is that microbes are literally short-circuiting," he said, adding that bacteria would lose electrons if they remain in constant contact with copper.

He noted that some astute ancient civilizations used copper as a purifier. For instance, the Phoenicians stored water in copper pots to make it drinkable.

The research community's interest in copper was rekindled about a decade ago, when a nursing study found fewer patient infections in hospital rooms with copper door handles. The copper industry has sponsored some of the initial research. But Dr. Schmidt's latest study was funded by the U.S. military.

He is now planning to do a large clinical trial to determine whether reducing the number of microbes on hospital surfaces actually translates into fewer infections. "Hospital administrators are reluctant to make capital purchases [of copper equipment]unless we can demonstrate a clear-cut benefit to patients."

There is, of course, a limit to what can be replaced with copper. But he sees no reason why a lot of commonly-used hospital equipment can't be made partly of copper - including computer mice and keyboards.

 

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