Antimicrobial Copper AND ITS APPLICATIONS History Copper has

Antimicrobial Copper AND ITS APPLICATIONS

History Copper has been used since antiquity for a variety of tools, weapons, and even medicine. 1 In ancient Egypt and Babylon bronze (alloy of copper and tin) shavings were applied to wounds to speed healing and stifle infection. 1 Fig. 11

Importance “Healthcare-associated infections (HAIs)–infections patients can get while receiving medical treatment in a healthcare facility. ” 2 Also known as nosocomial infections. Are a major, yet often preventable, threat to patient safety. ” 2 According to the CDC “On any given day, about one in 25 hospital patients has at least one healthcare-associated infection. ”

Importance Cont’d “In 2011, there were an estimated 722, 000 HAIs in U. S. acute care hospitals (see chart below). Additionally, about 75, 000 patients with HAIs died during their hospitalizations. More than half of all HAIs occurred outside of the intensive care unit. ” 2 Table. 12

How it Works Fig. 2 3

Surfaces Copper is the only antimicrobial surface material to be registered by the EPA. 3 Copper surfaces can reduce healthcare associated infections by 25%. 4 Pure copper is too soft and vulnerable to corrosion to make an adequate surface material. However, even in its alloyed form copper grossly outperforms stainless steel in killing microbes.

Surfaces Cont’d Copper can be made harder and more resistant to corrosion by alloying with zinc, tin or nickel. 5 This usually has a small effect on antibacterial properties. Pure copper and some alloy surfaces kill 99. 9% of bacteria within 100 minutes of exposure at room temperature vs. weeks for stainless steel. Kill times for pure copper can be seen in figures 3 and 4. Alloyed copper in figures 5 and 6. 6

Fig. 3. Decrease in bacterial numbers with exposure time on copper family alloys (99 -100%). Room temperature (20 °C). 6 Fig. 4. Decrease in bacterial numbers with exposure time on stainless steel (UNS S 30400). ● Room temperature (20 °C). 6

Fig. 5. Decrease in bacterial numbers with exposure time on copper nickel family alloys (70 -96%). Room temperature (20 °C). 6 Fig. 6. Decrease in bacterial numbers with exposure time on copper nickel zinc family alloys (55 -72%). Room temperature (20 °C). 6

HVAC Fungal spores can grow inside HVAC systems and spread throughout air ducts. This can lead to irritation or fungal infections in humans. 7 Copper is antifungal and will kill or stop the growth of mold. 7 In sites where mold is of high concern, copper alloys could be used in place of aluminum and steel for fins and ducts in air conditioning units. 7

Potential for preventing spread of fungi in air‐conditioning systems constructed using copper instead of aluminium Fig. 7 Aspergillus niger spores after 7 days exposure on copper (C 11000) (a) and aluminium (b); Aspergillus flavus after 4 days exposure on copper (c) and aluminium (d); and Aspergillus fumigatus after 4 days exposure on copper (e) and aluminium (f) assessed using epifluorescence microscopy. Spores or hyphae stained orange to red are metabolically active and those remaining green to yellow are not active. 7 Letters in Applied Microbiology Volume 50, Issue 1, pages 18 -23, 7 OCT 2009 DOI: 10. 1111/j. 1472 -765 X. 2009. 02753. x http: //onlinelibrary. wiley. com/doi/10. 1111/j. 1472 -765 X. 2009. 02753. x/full#f 1

Cost One estimate showed that copper implements cost about 30% more than their stainless steel counterparts. 4 The added cost of copper implements is recuperated by savings due to infections averted. 4 Time for return on investment of copper implements in a 20 bed ICU is 2 months. 4

Ongoing Research Mechanisms. SO MANY MECHANISMS! Copper ions regulate the proteins involved with wound healing and angiogenesis. Copper nanoparticles are being looked at as a possible wound dressing. 8

Questions Q. Is pure copper a valid alternative to stainless steel? No, it is too soft for most surface applications as well as being vulnerable to corrosion. Q. Are copper alloys antimicrobial? Yes. All copper alloys exhibit varying degrees of antimicrobial properties. Q. Do copper surfaces replace regular sterilization methods? No, standard sterilization methods are necessary but not sufficient. Copper surfaces provide a passive safeguard against microbes.

References 1. Bill Keevil Professor of Environmental Healthcare, University of Southampton. Copper is great at killing superbugs – so why don't hospitals use it? The Conversation. https: //theconversation. com/copper-is-great-at-killing-superbugs-so -why-dont-hospitals-use-it-73103. Published October 10, 2017. Accessed October 31, 2017. 2. Healthcare-associated Infections. Centers for Disease Control and Prevention. https: //www. cdc. gov/hai/surveillance/index. html. Published October 25, 2016. Accessed November 12, 2017. 3. How It Works. Cu. Verro Antimicrobial Copper Surfaces. https: //cuverro. com/scientific-proof/how-it-works. Accessed November 2, 2017. 4. Pineda I, Hubbard R, Rodriguez F. The role of copper surfaces in reducing the incidence of healthcare-associated infections: A systematic review and metaanalysis. Canadian Journal Of Infection Control [serial online]. Spring 2017; 32(1): 13 -24. Available from: CINAHL Complete, Ipswich, MA. Accessed October 31, 2017.

References Cont’d 5. Callister W, Rethwisch D. Materials Science and Engineering: an Introduction. -9 th Edition. John Wiley & Sons, Inc. 6. Wilks S, et al. The survival of Escherichia coli O 157 on a range of metal surfaces. International Journal Of Food Microbiology [serial online]. December 15, 2005; 105(3): 445 -454. Available from: MEDLINE, Ipswich, MA. Accessed October 31, 2017. 7. Weaver, L. , Michels, H. T. and Keevil, C. W. (2010), Potential for preventing spread of fungi in air-conditioning systems constructed using copper instead of aluminium. Letters in Applied Microbiology, 50: 18– 23. doi: 10. 1111/j. 1472 -765 X. 2009. 02753. x 8. Kornblatt A, et al. The neglected role of copper ions in wound healing. Journal Of Inorganic Biochemistry [serial online]. August 1, 2016; 161: 1 -8. Available from: Science. Direct, Ipswich, MA. Accessed October 31, 2017.