The effect of antimicrobial copper on pathogenic and environmental microorganisms in high-traffic non-clinical settings

The COVID-19 pandemic challenged researchers to explore alternative techniques to mitigate the transmission of microorganisms in high-traffic communities. Antimicrobial metals have been investigated due to their self-sanitizing features and ability to disrupt cellular activity. The objective of this project is to determine if the use of antimicrobial copper in high-traffic settings can reduce the spread of microorganisms that affect the human biome. Antimicrobial copper was implemented into the Thompson Rivers University (TRU) campus by engineering adhesive copper plates onto door handles in multiple buildings. Door handles that were chosen were in areas where high traffic was observed. TRU has approximately 13,000 students attending in-person classes and an above-average percentage of international students which may contribute to the diversification of environmental bacteria in the community. On campus, the efficacy of antimicrobial copper was tested over a four-month period, while classes were in session. Forty door handles were chosen for observation: ten external/environmental facing copper door handles, ten indoor copper door handles, ten external/environmental facing stainless-steel doorhandles, and ten indoor stainless-steel door handles. The door handles were swabbed using moistened Isohelix swabs. Metals were swabbed, and the microorganisms extracted under different environmental conditions were cultivated in Nutrient broth and Brain-Heart broth. The two broths were incubated in a shaking incubator at 37oC for 24 hours. This cultural approach established the baseline understanding of copper’s efficacy in a non-clinical high-traffic setting. Overall, the cultural approach has displayed a reduction in the diversity and concentration of microorganisms on the copper door handles versus stainless-steel. Additionally, non-cultural experiments were performed through forty DNA extractions of the same swabs used in the cultural experiments. The non-cultural approach supported cultural results indicating a difference in the microbial communities on copper versus stainless-steel door handles. Supporting past research, copper has demonstrated its ability to reduce the concentration of pathogenic microorganisms Staphylococcus and Pseudomonas in non-clinical settings. In future studies, antimicrobial copper should be considered as a preventative measure in high-traffic settings where cleaning protocol is limited.