| AVS 65th International Symposium & Exhibition | |
| Advanced Surface Engineering Division | Monday Sessions |
| Session SE-MoA |
| Session: | New Challenges and Opportunities in Surface Engineering |
| Presenter: | Nicole Ciacotich, Technical University of Denmark, Denmark |
| Authors: | N. Ciacotich, Technical University of Denmark, Denmark J.B. Rasmussen, Elplatek A/S, Denmark K.N. Kragh, University of Copenhagen, Denmark P. Møller, Technical University of Denmark, Denmark L. Gram, Technical University of Denmark, Denmark |
| Correspondent: | Click to Email |
Health care-associated infections (HCAIs) are one of the major causes of patient morbidity during hospitalization. Most, if not all, HCAIs are the consequence of proliferation and transmission of pathogenic microorganisms in hospitals, especially in intensive care units. In addition, a range of items and devices, including hospital furniture (bedrails, frames, door handles) are fomites that often have a high load of pathogenic agents.
In a previous study, we developed an electroplated copper-silver alloy as antibacterial coating on stainless steel to minimize adhesion and transfer of pathogenic bacteria on environmental surfaces. We have characterized the electroplated copper-silver alloy in its microstructure, chemical and electrochemical nature and demonstrated a pronounced antibacterial activity.
The purpose of the present study was to evaluate the antibacterial efficacy in a standardized surface adhesion tests against Staphylococcus aureus 8325. We determined the influence of chlorine and phosphorus compounds, well-known complexing agents of copper common in hand sweat and surface detergents, by comparing the antibacterial effect of stainless steel, silver, copper and copper-silver alloy. In presence of phosphates and chlorides, the copper-silver coating showed the highest antimicrobial efficacy followed by copper, compared to stainless steel and silver. In absence of chlorides, there was no statistically significant difference among the different metal surfaces.
We also demonstrated that the antibacterial effect of the copper-silver alloy was considerably reduced if the direct contact between surface and bacteria, but not the passage of ions, was prevented. This suggests that the antibacterial action is mainly due to the so-called contact killing mechanism, which is distinctive of metallic copper, rather than the release of copper ions.
Furthermore, we performed confocal microscopy of bacteria on copper-silver coated surfaces using a modified live/dead staining in order to follow over time the bacterial killing front at the surfaces. This demonstrated, as the assays based on counting, a rapid killing spreading upwards in the bacterial biofilm within 30 minutes.
In conclusion, we believe that the electroplated copper-silver coating can be an effective instrument limiting spread of pathogenic microorganisms causing HCAIs in hospitals and intensive care units.