How Copper Kills Microbes Including Norovirus
In findings presented at the American Society for Microbiology's 2013 General Meeting last week, researchers announced they have found a way to keep surfaces free from norovirus with copper and copper alloys.
The metal, according to researchers, quickly destroys the bacteria and could be employed in areas where norovirus outbreaks are common, like nursing homes and on cruise ships.
The finding is significant, given that there is no treatment for the infections that causes 267 million cases of gastrointestinal illness each year that takes a toll from vomiting and diarrhea.
The biggest impact of the virus has been on cruise ships and hospital wards. The remedy for outbreaks involves deep cleaning of surfaces where outbreaks have occurred that are costly. Norovirus is resistant to a variety of cleaning solutions.
Professor Bill Keevil, Chair in Environmental Healthcare at the University of Southampton, UK and lead researcher said in a press release, "The virus can remain infectious on solid surfaces and is also resistant to many cleaning solutions. That means it can spread to people who touch these surfaces, causing further infections and maintaining the cycle of infection. Copper surfaces, like door handles and taps, can disrupt the cycle and lower the risk of outbreaks."
The researchers say the virus dies quickly when it is exposed to copper or alloys that are 60% copper or more.
The bacteria is often spread in facilities from contamination of door handles, trays, railings and in clinical settings even I.V poles that can be harbingers of a variety of germs and fungi that are easily spread in hospitals. The virus is spread from water as well as contaminated food.
Adding copper taps could also help protect from norovirus because of its antimicrobial properties that extends to other food-borne bacteria as well.
In a two-year clinical trial, copper reduced infections in the intensive care unit up to 50 percent. The study that was conducted by 3 medical centers showed copper surfaces reduced the bacterial burden on surfaces in hospital ICUs by 83 percent.
Scientists say the way copper works to kill norovirus and other infectious microbes is by attacking the cell membrane. Once copper penetrates the outer membrane of the cell it then takes advantage of ‘holes’ in the cell wall to rob it of essential nutrients needed to survive.
Copper ions that get inside the microbial cells release enzymes that interfere with cell metabolism, causing bacteria, viruses and fungus to die.
Other infections that can be destroyed by copper include MRSA, Staph aureus, E.coli, Enterobacter aerogenes, Pseudomonas aeruginosa and Vancomycin-Resistant Enterococcus faecalis (VRE).
Adding copper to surfaces and other areas that are frequently touched where norovirus could be easily spread could rapidly destroy the virus; potentially protecting millions of people each year. The metal, used in high risk areas, could also save money that is lost from sick employees, shutting down hospital wards and cruise ships and help avoid use of costly disinfectants used to decontaminate surfaces that may not even be effective.
Image credit: University of Southampton
Article updated August 12, 2013