Copper Surfaces Can Destroy MRSA Pathogen Spread

A new study demonstrates that methicillin-resistant Staphylococcus aureus (MRSA) bacteria die on copper surfaces by a multifaceted attack of copper ions and reactive oxygen species (ROS).

Researchers at the University of Southampton (United Kingdom) conducted a study to examine the efficacy of copper in combating contamination of surfaces by MRSA via fingertips, which dry rapidly and may be overlooked by cleaning regimes, unlike visible droplets. The bacteria can be deposited on a surface by one person touching it, or via contaminated body fluids, and subsequently picked up and spread to other surfaces, potentially causing thousands of infections. In a previous study by the same researchers, a simulated droplet contamination of MRSA--such as in a sneeze or a splash—was killed on copper and copper alloy surfaces within 90 minutes.

The new study showed that the elimination of contamination of surfaces via finger was even faster, with a 5-log reduction of a hardy epidemic strain of MRSA (EMRSA-16) observed following 10 minutes of contact with copper, and 4-log reduction observed on copper nickel and cartridge brass alloys within 15 minutes. The researchers also found that bacterial respiration was compromised on the copper surfaces, and that superoxide ROS were generated as part of the killing mechanism. The study was published in the April 2016 issue of Applied and Environmental Microbiology.

“Our latest research shows that in simulated fingertip contamination of surfaces with millions of MRSA or MSSA, the cells can remain alive for long periods on non-antimicrobial surfaces – such as stainless steel – but are killed even more rapidly than droplet contamination on copper and copper alloys,” said lead author Sarah Warnes, PhD. “Exposure to copper damages the bacterial respiration and DNA, resulting in irreversible cell breakdown and death.”

“It’s important to understand the mechanism of copper’s antimicrobial efficacy because microorganisms have evolved various mechanisms to convey resistance to disinfectants and antibiotics,” added study co-author Professor Bill Keevil, PhD. “Our work shows that copper targets various cellular sites, not only killing bacterial and viral pathogens, but also rapidly destroying their nucleic acid genetic material so there is no chance of mutation occurring and nothing to pass on to other microbes, a process called horizontal gene transfer. Consequently, this helps prevent breeding the next generation of superbug.”

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University of Southampton