BEATING BACK INFECTION
According to the EPA registration, certain copper alloys: • Continuously reduce bacterial con- tamination, achieving 99% reduction within two hours of exposure.
• Kill greater than 99.9% of bacteria within two hours of exposure.
• Deliver continuous and ongoing antibacterial action, remaining effective in killing >99.9% of bac- teria within two hours, even after repeated wear and recontamination.
• Help inhibit the growth of bacteria within two hours of exposure before and after cleaning and sanitizing. Along with standard infection control practices, copper’s antimicrobial proper- ties could have a healthy impact on the spreading of disease-causing bacteria, according to the Copper Development Association (CDA).
For details on the CDA’s process of testing and negotiations for registering the metal with the (EPA), see “Bacteria Killer,” MODERN CASTING, June 2008, at
www.moderncasting.com.
ease of brazing, soldering, polishing and plating. Copper alloy products resist corrosion and friction, and retain their mechanical properties at low temperatures. Te prototype copper objects
developed for the study were made from various forms of copper alloys (see tables). Te base of the IV poles was cast copper, specifically C87610, a copper silicon alloy commonly used in architectural statuary, valve stems and pump components. Te research- ers noted that many of the techniques applied to develop the copper objects used in the study were chosen for speed and because of limited resources, resulting in prototypes, not com- mercially viable products. Several manufacturers have since made the investment in tooling and equip- ment to produce and sell marketable products for hospitals, according to Michels. For the study, copper alloy foil products were glued and fastened to standard plastic objects. Sheet, plate, rod and tube products were bent and welded to create new objects.
Fig. 2. This chart shows the antimicrobial efficacy of wrought copper, brass and stainless steel against the superbug MRSA.
Fig. 1. This chart shows the antimicrobial efficacy of various wrought and cast copper alloys, stainless steel and plastic against E. Coli O157:H7.
Fig. 3. This chart shows the antimicrobial efficacy of copper (C11000) against incremental cfu counts of MRSA.
Copper vs. Standard Hospital Equipment
While antibiotic-resistant, disease-
causing organisms can survive on environmental surfaces for substantial periods of time, standard cleaning practices remove much of these
pathogens from surfaces. How- ever, studies have shown that more than half of these surfaces are not adequately cleaned, according to the researchers, which paves the way for recontamination and the spreading of disease. Visitors and staff also f
October 2012 MODERN CASTING | 35
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