Copper for Preventing Microbial Environmental Contamination

Casey AL, Lambert PA, Miruszenko L, Elliott TSJ. Poster presented at the Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC), October 2008.

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Background: Transmission of infection involves various vehicles, including contaminated surfaces which have stimulated interest in antimicrobial materials. Copper has antimicrobial activity and its application in the clinical setting has been explored. Activity of copper against a wide range of hospital pathogens was also determined.

Methods: Microorganisms were applied to copper and stainless steel and viability determined over 3 hours at room temperature following their recovery into a universal neutralising solution. Viability on the metal was also determined by direct observation using epifluorescence microscopy of propidium iodide/SYTO 9 stained cells. A pilot study assessed the number of microorganisms on copper-containing toilet seats, grab rails, tap handles, light switches and door push plates on a busy medical ward. The copper-containing items harboured fewer microorganisms than standard items on a control ward (p=0.01). The study design was adjusted to sample copper-containing and control items on the same ward. A copper-containing: toilet seat, set of tap handles and a ward entrance door push plate were sampled and compared against equivalent standard items.

Results: The viability of Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumanii, Enterococcus spp. and Candida albicans was progressively reduced by at least 3 log 10 cycles over 3 hours on copper but not stainless steel surfaces. All copper-containing items harboured significantly fewer microorganisms (90%-100%) than their control equivalents.

Conclusions: Copper surfaces exhibit a pronounced antimicrobial action upon a range of pathogens, reducing viability over 3 hours contact at room temperature. Antimicrobial activity was also evident over a period of several months in the clinical setting. Copper surfaces may therefore be a valuable tool in preventing nosocomial infection.