Evaluation of the antimicrobial properties of copper surfaces in an outpatient infectious disease practice.

Surfaces in an outpatient setting are exposed to multiple patients b ecome colonized with microorganisms. Copper and alloys containing greater than 60% copper reduce bacterial burdens on solid surfaces by 99.9% within 2 hours.! Copper surfaces have been found to substantially diminish the density of bacte ria to levels below those considered a risk to patients for the acquisition of an infection. 1 .; In this study, we investigated the impact of copper surfaces on the b acterial burden found on high-touch surfaces of ph le-botomy chairs in an outpatient infectious disease clinic. Quantitative cultures were obtained from phlebotomy chairs located in an outpatient infectious diseases practice. Results from control (wood/composite) chairs and the copperized therapy chairs were compared. A total of 43 7 patients used the chai rs during the IS-week study period. Solid copper alloy metal (90% copper, 10% nickel) was inlaid across the arm tops and plastic trays of 2 phlebotomy chairs; the arm sides remained wood (Frigo Design , Brew-erton, NY). A control chair retained the original wood arms and plastic composite tabletop. All chairs were wiped down at the end of each day with a nonalcohol-based quaternary ammonium compound (QAC) cleanser wipe (PDf Sani-Cloth HB germicidal disposable wipes), and the floors of the therapy suites were cleaned once nightly with QAC solution (Virex). Chair locations were rotated every 3 weeks. The number of patients who used each chair was noted. Arm tops, arm sides, and tray tops of each therapy chair were cultured twice per week in midafternoon. Surfaces were wiped with moistened sterile rayon/polyester wipes (Kim-berly-Clark) and placed in sterile containers. Samples were delivered to the Medical University of South Carolina in cold packages within 18 hours. Bacteria were liberated from each wipe by adding 3 mL of sterile phosphate-buffered saline, 0.5% Tween 80, and 0.07% lecithin to a tube containing a wipe and vortexed at high speed for 1 minute. Samples (100 ;.tL) were plated onto tryptic soy agar (TSA; Becton Dickinson [BD]) , sheep blood agar (total microbes), mannitol salt agar (total staphylococci; BD), MacConkey agar (total gram negative; BD), ChromAgar methicillin-resistant Staphylococcus aurells (MRSA; BD), bile esculin azide (Hardy Diagnostics), and vancomycin agar (vancomycin-resistant Enterococcus [VRE]). Plates were in-cubated for 48 hours. The microbial burden associated with each surface was expressed as colony-forming units (CFUs) per 100 cm 1. The Kruskal-Wallis test was used to compare median microbial burden values (EpiInfo, …