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Copper study questions and answers

Question and answers about the copper trial at Selly Oak Hospital, funded by an education grant from the Copper Development Association.

With Dr Tom Elliott, Deputy Medical Director and Consultant Microbiologist, at University Hospitals Birmingham NHS Foundation Trust.

• Why did you carry out this clinical trial?
• How has the trial been conducted?
• What, specifically, have you found?
• What is the significance of that?
• Now you have completed this trial, what are the next steps?
• Given your experience, how significant are these findings?
• How would copper fit in with other infection prevention measures?
• How does copper actually kill the organisms?
• Is it safe for us to have copper in the ward?

Why did you carry out this clinical trial?

We had shown in the laboratory, with colleagues at Aston and Southampton Universities, that copper has antimicrobial properties. We wanted to show that, by putting copper in a clinical environment, it reduces the number of microbiological organisms associated with these devices.

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How has the trial been conducted?

We have been planning the trial for a year. We carried out a pilot study where we had a few items made by local manufacturers and had them installed in a ward. The first question we asked was: 'If you put a pair of taps in a sink does that reduce the number of organisms present in this environment?'

We demonstrated that there was a reduction. This meant it was worthwhile continuing with a proper, controlled study to see whether or not copper continues to have this property over a period of time. So we planned a crossover study. This is where you have items made from copper and you compare them with items made from standard products. For example, it could be chrome-plated taps or a push-plate made from plastic or aluminium or a grab rail made from chrome.

We compared copper with non-copper items on a busy medical ward. After a period of time, five weeks, we changed the items over. We sampled these items twice a day. First in the morning, at 7:00, before any cleaning had taken place on the ward, after the overnight period. Then we sampled again at 18:00 to see if there was any change in the organisms on the surfaces.

The samples included taking swabs, in the same way that we swab patients or wounds. We swabbed the surfaces and then we put them in up to seven different culture media to identify any bacteria or fungi which may have been present on the surfaces. We then counted the number of organisms on the surfaces. We did this over a 10 week period.

The reason we changed things over was to overcome bias. For example, it might be that one sink is used more frequently than another sink or one toilet is used more frequently than another. So, by doing this unique cross-over study, we are able to take this bias out and ensure that if there was an effect we could demonstrate it.

We carried out statistical analysis on the results which included the number of organisms per unit area of the devices. We then asked ourselves: 'Was there any difference and was it significant?' We have told the Interscience Conference on Antimicrobial Agents and Chemotherapy, the premier conference on infectious diseases and microbiology, [in Washington DC, USA] attended by 10,000 people, that the copper results in a significant reduction in the number of organisms on those surfaces compared to the standard products. This was despite absolutely scrupulous cleaning on the ward. The reason you get organisms on surfaces all the time is because we are touching them. We have environmental contamination. Everybody realises that. But the copper appears to be an intelligent metal so it augments already good cleaning processes. It is the first time I have ever seen the results shown. That environmental contamination is greatly reduced.

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What, specifically, have you found?

We have found that 90 to 95 percent of numbers of organisms on our standard items have been reduced in terms of total numbers on the copper. So we are seeing a significant reduction in the total numbers of organisms on the copper items, which is very exciting.

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What is the significance of that?

We know that organisms can spread round. Everyone is covered in organisms. Which means that organisms are everywhere, which means they are on surfaces, what we call fomites [any surface that can harbour infectious organisms]. But we also know organisms can spread by hands: hands on to surfaces, then spreading that way. So what it means is if we can keep our environment even cleaner, remembering that in our trial we had enhanced cleaning every two to three hours.

But you still do get contamination occurring because we are covered in organisms and we touch things. What it means is that our environment is even cleaner. What does this means for the patient? What it means is that the risk of picking up an infection is reduced. That is what it must mean. Because we know that is one of the vehicles where organism can spread from one surface to another by touching. So the results are very exciting.

They are more exciting than I thought we would achieve. From the laboratory results, they looked very promising. But, when you put it into the clinical environment, you always wonder whether or not it is going to work.

The findings of a 90 to 95 per cent killing of those organisms, even after a busy day on a medical ward with items being touched by numerous people, is remarkable. So it may well offer us another mechanism for trying to defeat the spread of infection.

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Now you have completed this trial, what are the next steps?

We need to do a longer study, and we are planning this for next year, a year's study, when we will look at other items so we will extend it to things like electric switches and drain tubes associated with sinks and grab rails to see whether other areas also have an equal success in reducing the numbers of organisms.

But I would expect that the results will cause a lot of interest in terms of the Department of Health. We know there is some interest already. And they would need to decide how this fits in with a strategy to prevent infection. The Department of Health has been doing a tremendous job in terms of already defeating infections in some areas. We have already seen a significant reduction in MRSA and C diff in the UK. [The question is] is this going to help them further in defeating these organisms?

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Given your experience, how significant are these findings?

I have been a consultant microbiologist for several decades and have got some experience in terms of fighting infections. Prevention of infections has been my goal in my career. And this is the first time I have seen anything as much as copper in terms of the effect it will have on the environment. We have talked about different agents in the past, cleaning agents like chlorine and hydrogen peroxide which have an immediate effect but not a long lasting effect like the copper.

We have shown in our study that copper has an effect for months. From our pilot study to the study we have presented in North America, copper has continued to work. It doesn't require further effect, further cleaning to continue to work to improve the surface. Copper is an intelligent metal.

So, from my viewpoint, from my experience and my career in terms of preventing infection, this is a very exciting finding, an unexpected finding, that perhaps copper will give us this advantage in keeping surfaces clean and perhaps challenging infections further.

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How would copper fit in with other infection prevention measures?

It is what I would call an intelligent metal. The copper is quietly working away in the background, killing organisms all the time. It needs to be part of what we call bundle of care in terms of an approach to preventing infection. In our trust, led by our senior nurse, we have what I would say is some of the highest quality infection prevention measures in terms of washing of hands, cleaning surfaces and managing the environment.

This gives us another arm, another weapon to fight infection which is around us and challenging us all the time. So I would see this in addition to the bundle of care we have at the moment.

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How does copper actually kill the organisms?

It's not clear at the moment how copper affects organisms. There are various theories on this. The most likely cause for the antimicrobial activity of copper in terms of killing organisms is the release of electron ions. What we think is happening is that the copper is being changed from cuprous to cupric. So there are two different forms and in doing so we have an electron release. And it is proposed that the activity that comes from the release of that electron is actually killing the organisms.

I would also propose that copper is affecting the membranes of the bacteria. They are all covered with a thick cell wall and within that cell wall is a membrane. I think that membrane activity is being affected by the copper. The membrane is important to the organisms because it is controlling food coming in and waste going out. If the copper is affecting the enzymes what it is doing is preventing the organisms from feeding, having nutrition and therefore killing them. So I think that is overwhelming the membrane as well.

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Is it safe for us to have copper in the ward?

We know that people wear copper bracelets for trying to prevent arthritis or the effects of arthritis developing and they don't get a reaction. We know that people put copper on their skins and there is no reaction. We know that having copper in the clinical area has not resulted in any reaction. The other main thing is that we have copper coins in our pockets and we handle copper every day. The fact is there are copper and brass items in our environment daily and we don't get reactions to it. It seems to be killing mainly the bacteria and fungal cells, which is very exciting.

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