Antibacterial activity of multilayer silver-copper surface films on catheter material

The antimicrobial activity of Ag, Cu, and layered Ag-Cu surface films, sputter-coated onto several types of catheter material, against clinical isolates of Staphylococcus epidermidis and Staphylococcus aureus was evaluated. When 20 microL of a suspension of S. epidermidis or S. aureus (2.68 x 10(6) colony-forming units/mL) was applied onto Ag-Cu- or Cu-coated butyl rubber, bacterial numbers were greatly reduced within 10 h, and eliminated within 24 h. In contrast, antibacterial activity was significantly less on uncoated or Ag-coated surfaces. Ag-Cu- or Cu-coated silicon rubber, polyvinylchloride, and teflon were even more effective than Ag-Cu- or Cu-coated butyl rubber. Ag-Cu layered surface films also showed antibacterial activity against Pseudomonas aeruginosa biofilm formation. Multiple metal surface film combinations show great promise in lowering the incidence of device-associated nosocomial infections.