Shouldering the bioburden


Metals with antimicrobial properties such as silver, copper or zinc incorporated into healthcare buildings, either as part of the internal furniture or building fabric can help to prevent the spread of healthcare acquired infections (HCAIs). Antimicrobial PVC-U trunking for cable management can reduce the bioburden of touch surfaces

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Antimicrobial metals – silver, copper or zinc – can be incorporated into buildings as part of the building fabric, furniture or at specific touch points to reduce bioburden. Marshall-Tufflex considers the use of such materials and reflects on the current lack of clear policy for their use in the UK NHS.

Contamination control is critical in cleanroom environments and healthcare facilities, with high levels of infection control required to prevent bacterial cross-infection and reduce bioburden levels. This crucial requirement has driven researchers to develop new and innovative approaches to minimising, controlling and killing bacterial pathogens, with the spotlight increasingly falling on the benefits offered by equipment and building products enhanced with antimicrobial properties. These are increasingly being recognised as straightforward and cost-effective methods of controlling and preventing infection in a wide range of applications, from laboratories to operating theatres.

From door furniture to privacy curtains, hand rails to cable management systems, floors to children’s toys, all manner of antimicrobial products are available, most of which are based on the antibacterial properties of metals such as silver and copper. And while systems vary in approach, using different metals as the active ingredient and employing different application techniques, all are geared to wiping out bacterial surface contaminants and preventing cross-contamination.

In the health arena, antimicrobials’ effectiveness against potentially lethal bacteria such as MRSA, Staphylococcus aureus, E. Coli, Salmonella and Klebsiella Pneumonia is well documented, with a growing number of healthcare providers installing them as a ‘belt and braces’ approach to infection prevention, coupled with rigorous hygiene and cleaning protocols. A number of UK hospitals already benefit from Marshall-Tufflex Bio Trunking Solutions’ antimicrobial PVC-U cable management systems in operating theatres, neo-natal units etc.

There is also growing awareness of how these ‘dual’ purpose products can potentially improve environments with high footfall or high risk of cross-contamination. This benefit may also extend to environments where it is imperative to control the bioburden of surfaces, with research indicating that spaces containing antimicrobial surface protection may also have lower bacteria counts on untreated surfaces.

It is important to point out that the presence of antimicrobials in no way lessens the need for cleaning and nor should it alter cleaning regimes. These products add an extra line of defence, killing bacteria between cleans, particularly in the winter months when bugs are more prevalent.

In general, antimicrobials use metal as their active ingredient – usually silver, copper or zinc. Silver has established antibacterial properties and is used widely within the medical profession for wound dressings, sterile equipment etc., where evidence-based data has shown its efficacy for preventing infection. Adapting it for use in building-related products that are frequently touched was a natural progression. Silver is the most widely used metallic biocide, with treated building products often costing little more than standard counterparts yet killing up to 99.9% of surface bacteria.

Cable management (trunking) systems that contain power and data cables are touch points so it made sense for manufacturers of trunking solutions, to combine silver ion technology into PVC-U products (Bio Trunking Solutions). The silver ion ingredient is mixed into the plastics solution during manufacture and activates when in contact with minute quantities of moisture in the air, disrupting key cell functions of bacteria and preventing them from reproducing, thereby rendering them inert very quickly given their rapid lifecycles. For this reason bacterial resistance is not an issue. The silver ion ingredient is non-leaching and does not wear out or wear off, ensuring the cable management system’s efficacy throughout its installed lifetime.

Antimicrobial trunking and other building systems come in two basic variants:

  • The silver ion formulation is added to the PVC-U during manufacture, ensuring it is evenly distributed throughout the product. Should the product get scratched, knocked or damaged, the active agent continues to do its job throughout the lifetime of the product.
  • The silver ion formulation is applied to the surface of products. However, once this coating is scratched, germs can penetrate the surface layer of these products and breed unchecked.

It is for this reason that Marshall-Tufflex advises using a product with an integral rather than surface applied antimicrobial agent.

Silver ion technology is proven to work. Consider the results of a study that compared two hospital wards, one equipped with a range of antimicrobial building products and the other with standard-issue products. The study revealed that bacterial counts on the antimicrobial products were 95% or more lower than bacteria counts taken from a similar product on the untreated ward. But the most interesting finding of the research was that samples taken from untreated surfaces in the ‘antimicrobial’ ward were 40% lower, suggesting that antimicrobial products have a positive effect on their environment as well.

Those thinking of using a silver ion antimicrobial system should confirm that it is registered with the Environmental Protection Agency (EPA) and compliant with the European Biocidal Products Directive (BPD). All Marshall-Tufflex Bio Trunking Systems are tested to ISO22196:2007, a quantitative standard, and the results show that the survival rate of the bacteria tested is less than 0.1%.

The metals copper and zinc are effective but not as widely used as silver ion technology. Copper is often a good choice for door furniture and other touch points such as handrails that naturally lend themselves both materially and aesthetically to being produced from metal. Some applications utilise copper contained within a brass product. However, specification of such hardware may not be suitable for all public locations given the ease with which such items can be stolen. They may also prove price prohibitive for some market sectors.

Barrier to product specification

Having established that building products enhanced with silver ion, copper or zinc technology are effective against some of the most virulent and dangerous bacteria, why aren’t more buildings equipped with them?

The answer to this question is discussed here only in the context of the UK health service. Initially it seemed that there was no NHS policy on the specification of antimicrobial products, with some Infection Control Panels interested and others largely unaware of the technology.

Marshall-Tufflex also discovered that many NHS managers did not realise antimicrobials could be incorporated into design and build materials and most did not consider design and build materials as part of a Healthcare Association Infection (HCAI) programme.

However, there is a policy. Contained within Health Building Note (HBN) 00-09 is reference to antimicrobial products that states: ‘there is, at present, no definitive data to support their efficacy in reducing health-care associated infections’.

At first, reading this appears a body blow to the whole antimicrobial building product lobby. But it is not. The DoH is simply stating that it needs hard data demonstrating that antimicrobial building products reduce HCAIs. And that means live tests on live patients in live healthcare environments. Until such research is possible trusts are free to specify and install antimicrobial solutions but each is left to make its own decision.

This piecemeal approach is a great shame, given the effectiveness of these products, which are tested to international standards and often cost only a little more than the standard version. It can be argued that, at the very least, they should be high on the list of considerations for wards and units treating more vulnerable patients, such as operating theatres, neo-natal, cancer units, geriatrics etc.

And the antimicrobial approach is not without controversy. One UK health trust has been quoted as stating that it is ‘worried’ that if the public gains information about antimicrobial building products they will want to attend only those hospitals equipped with these systems. Others are concerned that cleaning operatives will not work as effectively if they know these systems are installed. Marshall-Tufflex does not believe this is the case but it does highlight barriers to specification that must be overcome and misconceptions that need to be dispelled.

While there is no substitute for meticulous cleaning regimes and scrupulous personal hygiene, antimicrobial building products are a valuable additional weapon that can be used to great effect in the fight against superbugs and other bacteria. They work silently, invisibly and round the clock, killing bacteria, helping to prevent cross-infection and supporting cleaning plans. It is acknowledged that cleanrooms are only as clean as the products introduced into them – specifying and installing antimicrobial building products allows them to shoulder some of the bioburden.

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