Antimicrobial Properties of Copper Alloy Surfaces, with a Focus on Hospital-Acquired Infections

Michels H, Moran W, Michel J. Int J Metalcasting. 2008;2(3):47-56.

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Recent laboratory studies show that several bacteria, known to be human pathogens, die when they come in contact with dry copper and copper alloy surfaces at room temperature. The amount of live bacteria drops by several orders of magnitude, to zero, on copper alloys in one to two hours. In contrast, almost no reduction is seen in the concentration of live organisms on stainless steel after several hours and even days. Aluminum, painted and coated surfaces and plastics would also exhibit behaviour similar to stainless steel and show no effect. In addition, coatings and other surfaces claiming to be antimicrobial also showed little to no effect. These results suggest the selection of copper alloys for surfaces exposed to human touch can materially assist in reducing bacterial contamination, which should lead to a reduction in the transmission of infectious organisms. In order to make antimicrobial claims in the United States, the approval of the US Environmental Protection Agency (EPA) is required. The EPA-required efficacy testing is described and the test results are summarized. EPA registration of 275 cast and wrought copper alloys was received on February 29, 2008. It is anticipated that registration will facilitate the introduction of antimicrobial copper alloys in hospitals, nursing homes and other healthcare facilities, as well as schools, and public buildings. Some of the barriers to entry into the healthcare markets are mentioned.