By Peter J. Arsenault, FAIA, NCARB, LEED AP
Indoor environments are increasingly recognized as being an influencing factor on people’s health. Airborne transfer of germs and bacteria has received a lot of attention in recent times suggesting solutions focused on air ventilation and filtration. However, there has also been increasing attention paid to the role that the things we touch with our hands can play on our health. Specifically, it has been shown that just touching a surface that has been recently touched by someone who is sick, can mean that we can get the same sickness, even if the sick person touched it many hours or even days earlier. Finding ways to control or eliminate the spread of disease like this is becoming increasingly important in hospital settings as we might expect. But it is also emerging as a significant concern anywhere there is an unwanted risk of people becoming sick such as retirement communities, assisted living facilities, spa/wellness centers, schools, public buildings, and even in private residences.
The means of transferring illness from one person to another in an indoor setting is contained in infectious bacteria. It is these bacteria that are deposited on surfaces typically from the hands of an already infected person. When an uninfected person touches that same surface (such as a door handle, furniture, equipment, etc.), they are prone to pick up that infectious bacteria onto their hands. If that bacteria then gets transferred to something they are eating or drinking, or enters their body when they rub their eyes or nose, then they can become infected as well. Or they could shake hands or otherwise touch another person and transfer it to them. Frequent hand-washing is offered as a way to protect against becoming infected, but while that may interrupt the process, it doesn’t eliminate the core problem. It also requires constant diligence on the part of those who want to be protected.
This topic of the spread of infectious bacteria in indoor environments garnered some global attention recently. In July 2011, the World Health Organization (WHO) convened the First International Conference on Prevention and Infection Control in Geneva, Switzerland. Of particular concern was a growing realization that hospital patients were being infected with diseases while they were still in the hospital. Among the possible reasons for the rise in these hospital-acquired infections (HAIs) was the indoor environment. During the proceedings, Dr. Michael G. Schmidt of the Medical University of South Carolina gave a presentation where he declared, “The built environment in hospitals [furnishings, equipment, hardware, and more] likely accounts for at least 50 percent of the HAIs seen in the medical intensive care units.”1 Attributing half or more of these infections to the built environment is a clear wake-up call for those of us involved in the design, construction, and operation of such spaces. If we are truly protecting the health, safety, and welfare of the public, particularly those vulnerable already by being hospitalized, then these findings cannot be ignored.
There are plenty of other reasons that hospital administrators and healthcare professionals are paying attention to this phenomenon. Most disturbing is that each year in the U.S. alone, HAIs have been documented to claim on the order of 100,000 lives.2 That makes HAI-related deaths more prevalent than diabetes, influenza, pneumonia, AIDS, breast cancer, or Alzheimer’s disease. To make matters worse, it is costing a tremendous amount of money to treat those infections, upwards of $45 billion nationally.3 A part of that cost is the common medical treatment of using antibiotics to counteract the infections. But many antibiotics have made news lately because they are becoming less effective while new antibiotics aren’t being developed fast enough to be effective and save lives.
The trend isn’t improving. Some sources currently estimate that up to 80 percent of infectious diseases are transmitted by touch.4 What are hospitals doing? For one thing, they are promoting hand-washing campaigns for all staff and visitors. They are also increasing the use of alcohol gels and gloves wherever possible. And of course they are also mandating increased diligence with surface cleaning and disinfection by maintenance staff. But despite these aggressive approaches by hospitals to combat the issue, infection rates continue to rise. Clearly, alternative solutions are needed.
A New Approach: Bactericidal Hardware Surfaces
Product manufacturers have heard the problem loud and clear from hospital administrators and facility managers and have begun to respond with alternative proposals to improve the situation. The most promising approach is to create commonly touched surfaces out of materials that have the ability to kill infectious bacteria* while it is on that surface. Thus the problem bacteria* are prevented from growing and the risk of being spread to other people is reduced. Such materials with bacteria*-killing capability are referred to as bactericidal which is a term we may be familiar with from hand soap and disinfectants. Essentially, a bactericidal product is one that attacks and kills the bacterial microorganisms but without harming people.
As with most new offerings, though, product claims need to be carefully reviewed and verified. Of note, there have emerged a number of purported antimicrobial products that use a chemical coating and silver coatings, over a base product such as a work surface or a piece of hardware. There are some inherent problems with these coatings, however. The most obvious is that coatings of any type wear off over time from repeated touching or use by people; hence they don’t provide a long-term solution. Of course, as they wear off, the question also arises as to where they go. If they are leaching into the surrounding environment, the various chemicals that make up the coating can become a concern.
The biggest issue with coatings, however, is their real effectiveness as an antimicrobial agent. The U.S. Environmental Protection Agency (EPA) is the de-facto watchdog agency when it comes to human health claims. Products that can prove and demonstrate their effectiveness can be recognized and registered as truly bactericidal. Such recognized products can then make specific health benefit claims based only on what they have been able to demonstrate and prove through Good Laboratory Practice (GLP) testing and peer-reviewed scientific analysis. In the case of coatings, they have predominantly been found not to actually kill bacteria but rather they just limit or inhibit its growth. By virtue of limiting growth, a claim of some limited antimicrobial properties can be made, but since they do not actually kill bacteria, then no bactericidal claim can be made.
Coatings aside, there is one very successful material that has been recognized and registered with the EPA based on GLP as well as documented in over 40 peer-reviewed and professionally published papers. That material is a metal alloy that may take several forms but is copper based, such as different types of bronze or brass. These copper-based metal alloys have been shown to be the only class of solid material with the inherent ability to kill bacteria* harmful to human health. While copper alloys kill a wide range of bacteria, bactericidal copper alloy is registered to kill six specific bacteria* based on tested effectiveness against the following:
- E. coli O157: H7, a food-borne pathogen that has been associated with large-scale food recalls
- MRSA (Methicillin-Resistant Staphylococcus aureus), one of the most virulent strains of antibiotic-resistant bacteria and a common culprit of hospital- and community-acquired infections
- Staphylococcus aureus, the most common of all bacterial staphylococcus (i.e. staph) infections that can cause life-threatening diseases, including pneumonia and meningitis
- VRE (Vancomycin-Resistant Enterococcus faecalis), an antibiotic-resistant organism responsible for 4 percent of all healthcare-associated infections
- Enterobacter aerogenes, a pathogenic bacterium commonly found in hospitals that cause opportunistic skin infections and impacts other body tissues
- Pseudomonas aeruginosa, a bacterium that infects the pulmonary tracts, urinary tracts, blood, and skin of immunocompromised individuals
The science behind these results suggests that copper surfaces affect these bacteria in two sequential steps: The first step is a direct interaction between the surface and the bacterial outer membrane, causing the membrane to rupture. The second is related to these rupture holes in the outer membrane, through which the cell loses vital nutrients and water, causing a general weakening of the cell. How are those rupture holes created? Every cell’s outer membrane, including that of a single-cell organism like a bacterium, is characterized by a stable electrical micro-current. This is often called transmembrane potential, and is, literally, a voltage difference between the inside and the outside of a cell. It is strongly suspected that when a bacterium comes in contact with a copper surface, a short circuiting of the current in the cell membrane can occur. This weakens the membrane and creates holes. Another way to make a hole in a membrane is by localized oxidation or “rusting.” This happens when a single copper molecule, or copper ion, is released from the copper surface and hits a building block of the cell membrane (either a protein or a fatty acid). If the “hit” occurs in the presence of oxygen, then “oxidative damage” or “rust” occurs. An analogy is rust weakening and making holes in a piece of metal.
Once the cell’s main defense (i.e., its outer membrane) has been breached, there is an unopposed stream of copper ions entering the cell. This puts several vital processes inside the cell in danger. Copper literally overwhelms the inside of the cell and obstructs cell metabolism (i.e., the biochemical reactions needed for life). These reactions are accomplished and catalyzed by enzymes. When excess copper binds to these enzymes, their activity grinds to a halt. The bacterium can no longer “breathe,” “eat,” “digest,” or “create energy.” Experts explain the speed with which these bacteria perish on copper surfaces based on the multi-targeted nature of copper’s effects. After membrane perforation, copper can inhibit any given enzyme that “stands in its way,” and stop the cell from transporting or digesting nutrients, from repairing its damaged membrane, from breathing or multiplying.
Based on these results, bactericidal copper alloy is the only class of solid surfaces (i.e., not a liquid or gas that EPA has recognized) that is registered with the U.S. EPA and capable of supporting public health claims of killing harmful bacteria* that pose a risk to human health. No other solid surface material, no coating, nor any additive has this kind of registration and can currently support any such claims.
When bactericidal copper alloy is used as the material for producing hardware and accessories, then those products carry the same ability to kill the tested bacteria. The installed hardware is used in a conventional manner meaning that door handles, pulls, door plates, etc. that people need to touch on a regular basis to operate doors still function in the usual manner. Similarly, cabinetry can be equipped with hardware made from bactericidal copper for pulls and handles. And just as significantly, accessories such as hooks, shelves, switch plates, grab bars, and towel bars can be made of bactericidal copper alloy to help in those heavy-use locations as well.
Other applications are possible too including sink faucets and handles, handicapped door activation switches, or even custom-fabricated elements for particular needs in specific building designs. The bactericidal properties of the copper alloy used in any of these products will then help achieve healthier environments that can reduce the risk of transmitting environmentally acquired infections. And this is true whether it is used in hospitals, schools, living facilities, or anywhere else healthy indoor environments are a concern. By reducing contamination on these surfaces, it will lower the risk of transferring infectious bacteria* within buildings.
The most common traditional materials used in healthcare and other high-use settings include stainless steel, plastics, and composites. In particular, stainless steel has been a material of choice of hospitals for years because of its “clean look” and ability to be used for a variety of products and uses. However, tests have determined that it has no inherent abilities to kill bacteria.
Specifically, three tests were performed under GLP conditions following EPA protocols where stainless steel was used as the “control” surface to compare the differences between it and bactericidal copper alloy surfaces. These tests are described below with supporting graphs summarizing the results (see the online version of this article).
EPA Test 1: Efficacy as a Sanitizer
This test measures how many bacteria are still viable (living/growing) on a surface over time after the initial deposit on that surface. The graph shown (see online version of this article) is for one test of this type that started with an initial concentration of approximately 14 million Colony Forming Units (CFUs) of the antibiotic-resistant bacteria MRSA placed on a bactericidal copper surface. After only 2 hours of exposure, the tests revealed that virtually all of these bacteria (99.99 percent) were not viable meaning that they were in fact killed. By contrast, over the same 2-hour time period, over 70 percent of the MRSA exposed to the stainless steel control material remained viable or alive. At 6 hours of exposure the amount dropped slightly to approximately two thirds still viable—more than 8 million CFU compared to a starting sample of 13.2 million CFU still on this stainless steel surface. This is a dramatic display of the initial difference between bactericidal copper and stainless steel in terms of their inherent sanitizing capabilities.
EPA Test 2: Efficacy Will Not Wear Away
The EPA has developed a Residual Self-Sanitizing Activity Test to measure what the effects are of wear on a bactericidal surface. This test specifically measures bacterial count before and after a series of six wet and dry wear abrasion cycles during which bacteria are added in a standard wear apparatus. The process starts with the initial efficacy of bactericidal properties of a surface being measured after 2 hours as in the test above. Then the surface is exposed to a dry abrasive procedure to simulate wear. After 15 minutes, the surface is re-inoculated with bacteria. After 30 minutes the surface is then exposed to a wet abrasive/wear procedure. Another 15 minutes and the surface is again re-inoculated and 30 minutes later the same dry/wet cycle continues five more times for a total of six test cycles. A final 2-hour efficacy test is conducted at least 24 hours after the initial inoculation to show the final results of all of this wear and re-inoculation on a surface. The results showed that bactericidal copper alloy again performed with exemplary results with 99.99 percent of MRSA being killed. By comparison, stainless steel did not perform so well with a substantial amount (more than 1.3 million CFUs in this case) of bacteria remaining. The EPA uses this test to find out if the effective bactericidal agent will wear away or not. Based on this, the inherent bactericidal effectiveness of bactericidal copper alloy is expected to last the life of the product while a silver-based coating over a material may wear away over time and not be able to make the same claim.
EPA Test 3: Continued Effectiveness After Repeated Contamination
The question of repeated contamination is certainly legitimate, particularly in a setting with many people using a facility. Therefore, the EPA has developed a test procedure based on measuring bacteria counts after inoculating an alloy surface not just once, but eight times in a 24-hour period without any intermediate cleaning or wiping. In this test, 640,000 CFU of MRSA were inoculated on copper alloys, and within 2 hours, all were killed. Then without any surface cleaning performed, seven additional inoculations were performed (totaling 5.1 million CFU) on the same surface. After each time, the copper-alloy surfaces killed virtually all of the bacteria within a matter of hours. At the end of the 24-hour period only a very small amount of the initial CFU were found to still be viable showing that there was no cumulative build-up of any type from the repeated inoculations. This test showed the EPA that even after repeated contamination, and without cleaning the surfaces in between, bactericidal copper alloy surfaces are continually effective in killing MRSA bacteria over the course of a 24-hour day.
Stainless steel by comparison showed some notably poorer and more distressing results. As inoculations of the same 640,000 CFU each time were performed over the same 24-hour time period the total number of CFUs actually increased dramatically. One might expect that if the stainless steel wasn’t killing the bacteria, then the measured cumulative amount at the end of the test would total the 640,000 CFU times the 8 inoculations or 5.1 million CFUs. However, the test results showed that this repeated contamination on stainless steel actually produced an increase of the bacteria at a factor of over a four-fold growth. The measured total at the end of the 24-hour period was not 5.1 million CFUs but 22.9 million CFUs. These results certainly reinforce the need to constantly clean stainless steel surfaces and of course the EPA requires users to continue to follow all current infection control practices, including those practices related to cleaning and disinfection of environmental surfaces. EPA Test 3 was conducted only to illustrate the effect on the efficacy of surfaces that were not cleaned and exposed to repeated contaminations of large amounts of bacteria throughout a 24-hour period.
Based on the successful outcomes of these GLP tests, EPA registration and other investigations, the U.S. Environmental Protection Agency has stated “[Bactericidal copper] has been rigorously tested and [has] demonstrated antimicrobial activity. After consulting with independent organizations—the Association for Professionals in Infection Control and Epidemiology (APIC) and the American Society for Healthcare Environmental Services (ASHES)—as well as a leading expert in the field (Dr. William A. Rutala, Ph.D., M.P.H.) the Agency has concluded that the use of these products could provide a benefit as a supplement to existing infection control measures.”5 This appropriately worded statement confirms the bactericidal results of the laboratory tests and connects it to the real world applications in healthcare and other environments.
Laboratory testing, however, does not always replicate the actual conditions found in the real world. Rather it is typically the role of clinical trials conducted in functioning environments to validate those laboratory findings. In this case, such clinical trials were performed in hospitals in search of evidence that in clinical settings patients are at a lower risk of coming in contact with bacteria from copper-alloy surfaces than from plastic or stainless steel.6
The initial hypothesis of this study was stated as “Selecting touch-surface materials with the inherent ability to mitigate microbial burden can augment hand-washing and cleaning protocols and will minimize the risk of HAI transmission.” Participating hospitals included Memorial Sloan Kettering, R.H.J. VA Medical Center, and the Medical University of South Carolina. The work to carry out these trials was funded through a Department of Defense grant and broken into two phases: Phase I: Compare the effectiveness in reducing bacteria on copper vs. control surfaces; Phase II: Compare the influence of copper surfaces on reducing infection rates. Currently the findings from these trials are being finalized but early indications suggest that clinical results are similar to laboratory test results.
Of course the question will be posed by many as to the cost justification to use copper alloy materials instead of more conventional materials that undoubtedly cost less for their initial purchase. In that regard, the bigger picture of the life cycle and operation of the facility needs to be taken into account. There are at least three strong reasons for investing in bactericidal copper alloy in hospitals and the same reasoning can be used for other building types as well:
As we saw, conventional materials require rigorous cleaning and disinfecting to avoid not only the presence but the growth of infectious bacteria. Bactericidal touch surfaces are intended to supplement standard cleaning and hygienic practices, not replace it, but the net effectiveness of cleaning goes up notably creating surfaces with significantly less infectious bacteria*. Further, target cleaning levels are more readily achieved 24 hours a day/7 days a week. These results are achieved at a lower cost than alternative solutions—such as more cleaning, training, and supervision of staff. Further, these improved results occur with no added operating costs, no new equipment and no increase in supply costs.
Reduced Infections and Reduced Costs
As we saw earlier, hospitals are spending a great deal of money every year on treating unnecessary hospital-acquired infections (HAIs). A recent study identified that the average HAI adds 19.2 days to a hospital stay and increases the average charge by $43,000.7 The potential to reduce those dramatic costs by reducing the HAIs can obviously help create a very reasonable and short payback. Further, a decrease in HAIs means that patients are not being kept in the hospital as long which can increase the hospital “turn-rate” and contribute greater cost benefits for the operation.
This should be the most compelling reason to implement bactericidal copper alloy into hospital settings. The documented 2 million infections in the U.S. each year that result in 100,000 deaths do not bode well for claiming that hospitals are safe and healthy indoor environments. If clinical trials show that patients in rooms with copper alloy touch surfaces develop fewer infections, then that would suggest that tens of thousands of lives could be saved. With that level of success, it is not only a humanitarian issue of providing good and safe healthcare, but it becomes a risk management issue. If this simple solution is available and hospitals are adopting it as a standard of care, does that mean that a hospital that doesn’t implement it could be found negligent? That is a discussion for others, but one worth having.
Clearly, then the issue isn’t about first cost, but overall cost benefit and cost avoidance in the case of bactericidal surfaces. The question is less about how much does the material cost but so much more about how much does a preventable infection cost?
Specifying Hardware Made from Bactericidal Copper
When deciding to use bactericidal copper alloy hardware in a project, there are several relevant things to take into account when writing the specifications for it as touched on below.
While there are international standards to refer to for different metals including copper alloys such as bronze and brass, a specific certification of bactericidal alloy products is still under development. In the interim, the EPA has arranged for the Copper Development Association (CDA) to act as a watchdog organization to insure that product manufacturers are in proper compliance with EPA registration requirements before making any health related claims about their products. The CDA is using a supporting Certification Mark that uses the chemical symbol for copper (Cu) and the plus sign together: Cu+. This Cu+ mark certifies that the copper alloys being sold for bactericidal applications meet the high quality assurance standards set forth by the copper industry and the regulatory standards set forth by the EPA. Surfaces from suppliers with this mark are presented as being in full compliance with EPA registrations. Therefore, their associated labeling, advertising and marketing claims are also presented as being compliant particularly in regards to public health claims that their product surfaces have been shown to kill identified bacteria. It also means that only approved alloys are used that comply with EPA content and purity levels.
|The Copper Development Association (CDA) issues the Cu+ mark to a product that can prove it has met and complied with the EPA requirements to be termed bactericidal copper.Image courtesy of Rocky Mountain Hardware|
There are other benefits of calling for this certification mark as well since these products also use a required UNS (Unified Numbering System) designation. This insures that the alloys contain the required active copper concentrations to be effective under EPA test protocols, and verifiable other ingredients to be consistent with the EPA registration.
When specifying bactericidal copper alloy products, a 60 percent minimum copper content in the alloy must be called for that must also match the EPA tested alloy make-up. If there is any doubt, then request submittals showing the registration and tested bactericidal make-up as tested.
The market has responded quickly and quite well to making a wide variety of touch surface products available to specify and include in new construction and renovation building projects. Hence it is possible to specify a full suite of hardware and accessories made from the same uniform materials and provide a consistent aesthetic appearance. Therefore, the copper alloy material of choice can be specified in sections that address:
- Door hardware including various functions and lock mechanisms
- Push plates and pull handles
- Cabinet hardware including pulls and knobs
- General bathroom and other accessories such as hooks, towel bars, etc.
- Handicapped accessories such as grab bars and door opening switches
- Furniture pieces such as serving trays or wall shelves
- Plumbing faucets and handles
- Electrical switch plate covers
- Custom pieces for decorative or functional purposes
All of these are available in a range of finishes that belie the usual image that may come to mind when thinking about bronze and brass. Three different EPA registered alloy mixtures for bronze for example can be finished to create a range of appealing color choices. Hence, rose bronze, silicon bronze, or white bronze can all be finished in either a matte or brushed finish. The resulting products are readily distinguishable as “bactericidal” in that they do not look like stainless steel. The warm and natural hues still project a clean, professional, medical looking appearance that is suitable for a variety of building types. These finishes are tarnish-resistant, strong, and durable since they are integral to the product itself and not applied or coated. Further, they are easily cleaned and the surface holds up well to standard hospital cleaners while still maintaining its inherent bactericidal efficacy over the full life of the product.
Bactericidal copper alloy products can also be specified to help with green building design. Since they are made from natural materials they are commonly available with up to 80 percent recycled content. At the end of their useful life they are 100 percent recyclable. Since they are free from any coatings, finishes, sealants, or adhesives no toxic additives are introduced meaning there is no formaldehyde or other VOCs, no PVC no phthalates, no heavy metals (i.e. lead, cadmium, arsenic), no perflourinated chemicals (PFC’s), and no dioxins. Finally, most of these products are made in the USA meaning that regional sourcing may be possible in some areas.
Cleaning and Maintenance
Bactericidal copper alloy products are tarnish resistant, easily maintained, and hold up well to standard cleaners. It is important, however, to instruct both contractors that are installing bactericidal products and the end users on some cleaning basics. In order to maintain bactericidal efficacy, surfaces cannot be coated or waxed since that puts a barrier between the surface and any bacteria. The use of buffing or polishing compounds that leave film are similarly not allowed. Surfaces should still be cleaned to regular hospital protocols (i.e., appropriate disinfectants, frequency etc.). This is important for all to understand since copper alloys have been shown to be an effective supplement to standard cleaning practices, but are not intended to replace normal cleaning.
An important goal of a safe indoor environment, particularly in healthcare settings, is to reduce the risk of transmitting hospital-acquired infections (HAI’s) and similar conditions in other buildings due to the transfer of infectious bacteria on touch surfaces. Previously, the only real options have been more frequent cleaning, more supervision, and more sophisticated cleaning equipment. Twice as much cleaning effectively doubles the cleaning budget. More cleaning, equipment, and better supervision costs even more. Bactericidal copper alloy hardware and accessories provide real help with this problem as a supplement to regular cleaning with proven results. Laboratory test surfaces demonstrated ongoing effectiveness by killing 99 percent of tested bacteria* within 2 hours or less. Further, bactericidal copper alloy has been shown to actively kill bacteria 24 hours/day, 365 days/year making it more effective than additional cleaning and supervision. The value of its use can be quickly realized through improved cleaning effectiveness, improved patient care, better indoor health, and reduced operating costs.