Clinical researchers were challenged to answer the question ‘are the antimicrobial properties of copper too good to be true?’ at the University of Bern Research Conference recently.
And the answer—provided by Professor Mark Solioz of Russia’s Tomsk State University, in his presentation—is not only an emphatic 'no', but that it should be possible to improve even further the antimicrobial properties of copper, based on his research.
Solioz presented a summary of laboratory research from groups around the world, reporting that copper is a powerful antimicrobial with rapid, broad-spectrum efficacy against bacteria and viruses.
When pathogens come into contact with a copper surface—such as a door handle or light switch—they are rapidly destroyed: a process referred to as contact killing. Contact killing by copper has been demonstrated for at least 90 bacterial species, 30 types of fungi, and 20 different viruses and, in a recently-published paper, Solioz observes ‘it can safely be assumed that all bacteria and viruses are sensitive to contact killing by copper.’
The presentation further covered the practical applications of copper—and the many copper alloys sharing its antimicrobial properties, collectively called antimicrobial copper—in clinical trials around the world, which agree on an up-to-80% reduction in bacteria on antimicrobial copper touch surfaces compared with non-copper equivalents. A seminal, multi-centre US clinical trial further reported a 58% reduction of healthcare-associated infections in an intensive care unit when just six key touch surfaces in the rooms were replaced with antimicrobial copper equivalents.
Solioz is particularly interested in the mechanism of contact killing of pathogens by copper. His reasoning for this is the necessity to explore two key points: how to optimise the antimicrobial performance of solid, copper-based materials; and to address concerns about the possibility of organisms developing resistance to copper.
“The antimicrobial efficacy of copper and copper alloys is well established, and a large number of products are already available on the market and in use in hospitals and other healthcare environments,” he said.
“With that in mind, I want to ask the question: how can we enhance that efficacy? How can we make copper work even better for us? I believe the answer lies in new alloys which exhibit enhanced release of copper ions by galvanic processes.”
Regarding the chances of organisms developing resistance to copper, he added: “Our research has shown us that contact killing involves multiple pathways and is extremely rapid, so there is very little chance of any organism developing resistance. Furthermore, there is no growth of bacteria on dry, metallic copper surfaces, so bacteria have no opportunity to exchange genes. Gene transfer between bacteria is a key factor in the development of antimicrobial resistance. This suggests a broader role for copper—beyond infection control—in helping to reduce the general spread of antimicrobial resistant organisms.”
He concludes that antimicrobial copper touch surfaces show great promise—in the lab and in clinical trials—for boosting other measures against infection and supporting the fight against antimicrobial resistance.
And he called on applied scientists to take the research further and find the best applications for this powerful property of copper.
However, other measures also have to be taken to control healthcare-associated infections, such as screening of personnel for Staphylococcus aureus, quarantines for newly-admitted patients, and reduced use of antibiotics.