Evaluation of copper alloys for reducing infection by methicillin resistant Staphylococcus aureus and vancomycin resistant Enterococcus faecium in intensive care unit and in vitro

Abstract

Background/Aims: Multi-drug resistant pathogens are increasing among healthcare-associated infections. It is well known that copper and copper alloys have antimicrobial activity. We evaluated the activity of copper against bacteria in a hospital setting in Korea. Methods: This study was conducted in a laboratory and medical intensive care unit (ICU). Methicillin resistant Staphylococcus aureus (MRSA) and vancomycin resistant Enterococcus faecium (VRE) were inoculated onto copper, copper alloy and stainless steel plates. After 24 hours of incubation, colony-forming units (CFU) were counted in the laboratory. Two similar rooms were chosen in the ICU; one room had copper-containing surface, and the other room contained items with a stainless steel surfaces. Items were sampled weekly for 8 weeks when the rooms were not crowded and when the rooms were busier with healthcare workers or visitors. Results: In vitro time-kill curves showed copper or, a copper alloy yielded a significant reduction in MRSA and VRE CFUs over 15 minutes. Upon exposure to stainless steel plates, CFUs were slowly reduced for 24 hours. In vivo, MRSA CFUs were lower in rooms with copper-containing surfaces compared with controls, both after cleaning and after patients had received visitors (p < 0.05). Analysis of VRE revealed similar results, but VRE CFUs from copper-containing surfaces of drug carts in the ICU did not decrease significantly. Conclusions: Copper has antimicrobial activity and appears to reduce the number of multi-drug resistant microorganisms in a hospital environment. This finding suggests the potential of the use of copper fittings, instruments and surfaces in hospital.