Antimicrobial Surfaces as a Tool to Support HAI Prevention

By Sue Barnes, RN, CIC, FAPIC

More than 1 million healthcare associated infections (HAIs) occur within the U.S. healthcare system every year. According to a study per-formed by the Centers for Disease Control and Prevention (CDC), approximately 1 of every 25 hospitalized patients in the U.S. develop an HAI, meaning that nearly 650,000 patients contract one of these infections annually. These infections can lead to serious illness and result in the loss of thousands of lives each year. In addition they impose a tremendous financial burden, estimated to be more than a billion dollars annually in the U.S.1

Antimicrobial impregnated soft and solid surfaces are increasingly being offered by a variety of companies as a tool to reduce the burden of pathogens in patient’s environment and the associated risk of transmission and development of healthcare associated infections.  There is evi-dence to conclude that a patient’s environmental contamination increases the risk of infection.2 Emerging products designed to address that problem include antimicrobial soft and solid surfaces.  These products claim to reduce the burden of microbes on surfaces, and some claim to directly reduce the incidence of infection. These include antimicrobial sinks, door knobs, bed rails, paint, carpet, furniture, patient gowns, employee scrubs and privacy curtains and other near patient items.  The antimicrobials used to manufacture solid surfaces include copper, silver, and organosilane. Antimicrobials used to impregnate soft surfaces include triclosan, silane quaternary ammonium, zinc pyrithione and silver based compounds. In the era when affordable healthcare is a focus of legislation and regulation, it is important to understand the evidence of efficacy for emerging technologies, in order to make decisions that consider true versus potential benefit, as well as product cost.

Antimicrobial solid and soft surface products are designed to reduce burden of microbes in the patient’s environment in order to reduce the risk of infection.  As a rule these products are more expensive than non-impregnated products. 

The Environmental Protection Agency (EPA) requires manufacturers of products containing antimicrobial chemicals to provide evidence of efficacy in order to register them.  There is an exemption for use of antimicrobial chemicals as a preservative.  Consequently it is important to determine whether added antimicrobials in healthcare products are designed for the preservation, to prevent staining or odors, or to prevent infection.

Earlier this year Muller, et al. published a systematic review of studies focused on the use of antimicrobial surfaces in patient rooms.  The re-view included study outcomes including infection rates and microbial contamination. Eleven of the studies focused on the efficacy of metal alloys, primarily copper and silver, as well as organosilane. One study assessed efficacy of copper impregnated textiles in long-term care facilities. All studies concluded there was a reduction in microbial contamination and/or infection rates, though all were judged to be very low-quality research.

Microbes are known to contaminate and re-contaminate the healthcare environment immediately after cleaning, or even persist despite cleaning. Manual cleaning of the healthcare environment though effective if performed per protocol, will never be perfect due to human fac-tors. Consequently, given the virulent pathogens transmitted via environmental surfaces such Clostridium difficile, there has been increasing attention over the past decade on development of technologies that are adjunctive to manual cleaning. One category of adjunctive technology includes antimicrobial soft and solid surfaces.  These products are designed to reduce the number of microbes on surfaces that can be trans-ferred by hands and inanimate objects among patients and healthcare workers. Many of these microbes, including pathogens that cause serious healthcare associated infections, can survive for days to months on dry surfaces. Spore-forming bacteria, including Clostridium difficile, are among the longest survivors.3 

It is clear that routine manual cleaning and disinfection (with friction) is sufficient to remove the majority of microbes from patient environments if performed correctly and comprehensively.  However, any pathogens that are missed or persist can be implicated in transmission of infection. Huang, et al. demonstrated that hospital patients admitted to rooms where patients infected with antibiotic resistant organisms had just been discharged, had a greater chance of acquiring these microbes.4 It is suggested by manufacturers that these antimicrobial surfaces can provide an additive effect to manual cleaning, and thereby reduce the risk of persistent and re-contaminated surfaces near the patient.

The suggested potential adverse outcomes associated with antimicrobial impregnated surfaces include cost. Adding copper surfaces is about 15 percent to 20 percent more expensive than using traditional stainless steel. A typical U.S. hospital room contains about $100,000 of goods and equipment, and the average cost to outfit a hospital room with antimicrobial copper items is about $5,000.8

Another theoretical concern is the development of pathogen resistance to antimicrobials with overuse.5 In addition, there is the potential risk of environmental toxicity. Some of the products contain silver or copper particles, which are considered environmental toxins.6 It is not yet clear whether these materials release enough metal into rinse water upon cleaning or into the soil upon disposal to result in a true danger. 

Novel antimicrobial impregnated soft and solid surfaces offer the potential for reduced surface contamination. It is proposed that faster die-off of pathogens on a surface can significantly reduce the amount of time that a surface is capable of transmitting disease, and can also reduce the population of pathogens available for transmission by healthcare hands to a susceptible patient.

A systematic review of studies designed to measure the impact of antimicrobial surfaces was published in 2016 by Muller, et al.7  Surfaces studied include bed rails, tables and textiles (sheets, privacy curtains, clothes). There were seven studies assessing efficacy of copper solid surfaces, two assessing silver surfaces and two assessing organosilane (organometallic compounds containing carbon–silicon bonds). The paper concluded that of all antimicrobial surfaces only copper was shown to definitively reduce microbial counts, and two copper studies showed a reduction in HAI. The paper further states that “Copper surfaces harbor fewer bacteria than non-copper surfaces. One study of copper surfaces and one of copper textiles showed a reduction in the incidence of healthcare associated infections.” However, the review concluded that overall the quality of all studies published to date was considered to be very low, due to “bias as a result of uncontrolled design, the absence of appropriate randomization, allocation concealment and incomplete blinding.”7

Given the current quality of efficacy evidence, and the focus on affordable healthcare, routine use of these products is unlikely at present.  Though according to a Washington Post article in 2015 several “at least 15 hospitals across the country have installed, or are installing, copper components on “high-touch” surfaces including faucet handles, cabinet pulls, toilet levers, call buttons and IV poles.”8 These early adopters are possibly motivated by the fact that one infection can add $45,814 in associated healthcare costs, and under the Affordable Care Act, hospitals with higher infection rates and other patient injuries face decreases in their Medicare reimbursements.9

Additional studies are needed not only to measure the direct impact of these products on infection incidence, but also to further investigate the potential for development of bacterial resistance and environmental toxicity.

Sue Barnes, RN, CIC, FAPIC, is an independent clinical consultant. She is board-certified in infection control and prevention, and was granted the designation of fellow of APIC in 2015 (FAPIC).  She has been in the field of Infection Prevention since 1989.  She has participated in the development of a number of APIC guides, and served as a speaker for organizations including AORN and APIC.  In addition Barnes has been published in journals including AORN Journal, American Journal of Infection Control, the Joint Commission Source for Compliance Strategies and the Permanente Journal. She served on the National APIC Board of Directors from 2010 to 2012, and the San Francisco chapter board of directors for the past 10 years.

References:
1. AHRQ July 2016: https://psnet.ahrq.gov/primers/primer/7/health-care-associated-infections
2. Kramer A, Schwebke I, Kampf G. How long do nosocomial pathogens persist on inanimate surfaces? A systematic review. BMC Infect Dis 2006;6:130.
3. Mikolay A, et al. Survival of bacteria on metallic copper surfaces in a hospital trail. Appl Microbiol Biotechnol 2010;87:1875-1879.
4. Huang SS, Datta R, Platt R. Risk of acquiring antibiotic resistant bacteria from prior room occupants. Arch Intern Med 2006 Oct 9;166(18):1945.
5. Percival, SL, Bowler PG, Russell D. 2005. Bacterial resistance to silver in wound care. J Hosp Infect 60: 1-7.
6. Seligman PF, ed. A. Zirino, ed. Technical Document 3044 November 1998 Chemistry, Toxicity, and Bioavailability of Copper and Its Relation-ship to Regulation in the Marine Environment Office of Naval Research Workshop Report http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2&doc=GetTRDoc.pdf&AD=ADA356956
7. Muller MP, et al. Antimicrobial surfaces to prevent healthcare-associated infections: a systematic review. Journal of Hospital Infection 92 (2016) 7-13.
8. Sun LH. The bacteria-fighting super element that’s making a comeback in hospitals: copper. The Washington Post. Sept. 20, 2015 https://www.washingtonpost.com/national/health-science/the-bacteria-fighting-super-element-making-a-return-to-hospitals-copper/2015/09/20/19251704-5beb-11e5-8e9e-dce8a2a2a679_story.html?utm_term=.56d424e0caf8
9. Waknine Y. Hospital infections cost billions, study shows. Medscape Medical News. September 3, 2013. http://www.medscape.com/viewarticle/810372