Inhibitory Effects of Copper, Brass, and Stainless Steel Surfaces on Multidrug-Resistant Microorganisms

Background: The aim of this study was to analyze the inhibitory effects of copper, brass (78% copper, 22% tin), and stainless steel surfaces on multidrug-resistant Acinetobacter baumannii (MRAB), extended-spectrum beta-lactamase (ESBL) Escherichia coli, and carbapenem-resistant Klebsiella pneumoniae (CRKP). Methods: MRAB, ESBL E. coli, and CRKP were isolated at Uijeongbu St.Mary’s Hospital in 2020. A. baumannii ATCC BAA-747, E. coli ATCC 25922, and K. pneumoniae ATCC 700603 were used as reference strains. The initial bacterial cell count of each inoculum was adjusted to 8 log CFU/mL using phosphate buffered saline, Copper, brass, and stainless steel plates were inoculated with 9 mL of MRAB, ESBL E. coli, and CRKP inoculum solutions. The bacterial cell count was measured from the beginning to the 20th day in an incubator maintained at 35°C. Results: MRAB, ESBL E. coli, and CRKP isolates were not detected on the copper and brass plates after 4, 5.5, and 6.5 hours, respectively. MRAB, ESBL E. coli, and CRKP isolates were not detected on the stainless steel plate after 15, 20, and 20 days, respectively. The bactericidal effects of copper and brass were much stronger than those of stainless steel. Conclusion: The use of copper and copper alloys should be considered to prevent cross-infection in hospitals.