October_AMP_Digital

A D V A N C E D M A T E R I A L S & P R O C E S S E S | O C T O B E R 2 0 1 7 2 3 to kill more than 99% of [said] bacteria even after repeated contamination.” In contrast, even when non-copper surfac- es are regularly cleaned, they will soon harbor infectious organisms again as a result of being frequently touched by contaminated hands or gloves. CLINICAL TRIALS Healthcare facilities such as hos- pitals, nursing homes, clinics, and re- habilitation facilities are a breeding ground for pathogens, posing dangers for patients and caregivers alike. Ac- cording to a study published by the Centers for Disease Control and Pre- vention, in the U.S. alone, more than 1.7 million hospital patients acquired a bacterial, viral, or fungal infection in 2002, resulting in nearly 99,000 deaths and additional treatment costs in the range of $40 billion [4] . These alarming numbers com- pelled researchers to propose a clinical trial to determine if antimicrobial cop- per alloys could help make a difference. With funding from the U.S. Department of Defense, the researchers embarked on a two-phase study, focusing their efforts on the medical intensive care units, or MICUs, at three hospitals: • Memorial Sloan Kettering Cancer Center, New York • Medical University of South Carolina, Charleston • Ralph H. Johnson VA Medical Cen- ter, Charleston, S.C. COPPER ON CALL In the first phase of the study, researchers examined several MICU rooms to determine which surfaces and objects harbored the greatest number of bacteria [5] . Based on their findings, the following six items were fabricated from copper alloys and retrofitted in at least one MICU room in each hospital: • Caps on the side rails of the pa- tient’s bed • Nurse call button • Arms of the visitor’s chair • Over-the-bed patient tray table • Data input device (i.e., computer mouse, touch screen bezel, or laptop palm rest) • IV drip pole An example of one of the copper- retrofitted rooms is shown in Fig. 2. Most of the retrofit components were made of 90 wt%Cu−10 wt%Ni alloy due to its tarnish resistance, durability, and ease of fabrication. Over a 43-month period, research- ers measured contamination levels in both retrofitted and standard rooms in the three participating hospitals. The results, displayed in Fig. 3, show that in all but one case the copper surfac- es harbored anywhere from three to 20 times less bacteria than compara- ble stainless steel, plastic, or painted low-carbon steel surfaces. The only ex- ception is the data input device where the bacterial counts were roughly the same. INFECTION CONNECTION In the second phase of the study, researchers (without informing hospital Fig. 1 — Plot of surviving MRSA bacteria on various material surfaces expressed in terms of colony forming units per square centimeter. Researchers used 1-cm 2 coupons, coating the surface with 70 million MRSA CFUs/cm 2 . The pure copper test sample killed all of the bacteria in 90 minutes, while it took brass (80 wt%Cu−20 wt% Zn) about three times longer to achieve the same result. Stainless steel (18 wt%Ni−8 wt%Cr−74 wt% Fe) had almost no effect. Fig. 2 — A typical patient room retrofitted with copper alloy components. Four of the six copper retrofits are visible, including the over-the-bed table, IV pole, data input device (touch screen bezel), and caps on the bed rails.