From Laboratory Research to a Clinical Trial: Copper Alloy Surfaces Kill Bacteria and Reduce Hospital-Acquired Infections

Abstract

Objective: This is a translational science article that discusses copper alloys as antimicrobial environmental surfaces. Bacteria die when they come in contact with copper alloys in laboratory tests. Components made of copper alloys were also found to be efficacious in a clinical trial.

Background: There are indications that bacteria found on frequently touched environmental surfaces play a role in infection transmission.

Methods: In laboratory testing, copper alloy samples were inoculated with bacteria. In clinical trials, the amount of live bacteria on the surfaces of hospital components made of copper alloys, as well as those made from standard materials, was measured. Finally, infection rates were tracked in the hospital rooms with the copper components and compared to those found in the rooms containing the standard components.

Results: Greater than a 99.9% reduction in live bacteria was realized in laboratory tests. In the clinical trials, an 83% reduction in bacteria was seen on the copper alloy components, when compared to the surfaces made from standard materials in the control rooms. Finally, the infection rates were found to be reduced by 58% in patient rooms with components made of copper, when compared to patients' rooms with components made of standard materials.

Conclusions: Bacteria die on copper alloy surfaces in both the laboratory and the hospital rooms. Infection rates were lowered in those hospital rooms containing copper components. Thus, based on the presented information, the placement of copper alloy components, in the built environment, may have the potential to reduce not only hospital-acquired infections but also patient treatment costs.

Keywords: built environment; clinical trial; environmental surfaces; hospital-acquired infections; translational research.

Figure 1.

Continuous reduction test results for methicillin-resistant Staphylococcus aureus on copper alloy C110 (99.9% Cu; Anderson & Michels, 2008).

Figure 2.

Initial inoculum level shortens the time for copper alloy C110 (99.9% Cu) to kill methicillin-resistant Staphylococcus aureus (Noyce, Michels, & Keevil, 2006b).

Figure 3.

Residual self-sanitizing test, where bacteria counts are measured before and after six alternate wet and dry wear cycles, and the surface is reinoculated with bacteria before each cycle (Anderson & Michels, 2008).

Figure 4.

Microbial burden measured on six objects, in the noncopper rooms (dark gray bars) and copper rooms (light gray bars; Schmidt, Attaway, Sharpe, et al., 2012).

Figure 5.

Distribution of healthcare-associated infection versus microbial burden measured in the intensive care unit rooms during the patient stay (Salgado et al., 2013).