Nanocrystalline Silver Layer of Knitted Polyester Outperforms Other Silver-Containing Wound Dressings in an In Vitro Wound Model

Background Silver possesses cytotoxic properties against many microorganisms and is regularly used in wound care. Current evidence supporting the use of one type of silver-containing wound dressing (SCWD) is insufficient. Methods To examine the ability of selected SCWDs to inhibit the growth of two strains of bacteria (E. coli and S. aureus) commonly found in wounds, an in vitro wound model was used. Bacteria were applied to the surface of nutrient agar and a piece of each SCWD was applied to the bacteria. The plates were incubated at 37°C overnight. The zone of inhibition (ZI) around each SCWD was measured in cm2. Results The mean ZI for Acticoat Flex-3 on E. coli was 1.59 ± 0.15 cm2, which was significantly greater than that observed for Aquacel Ag (p<0.001), Mepilex Ag (p<0.0001), Mepitel Ag (p<0.001), Optifoam (p<0.0001) and Tegaderm Alginate Ag (p<0.01), but statistically indistinguishable from Maxorb II Ag. The mean ZI on S.aureus was 1.21 ± 0.16 cm2, which was greater than Aquacel Ag (p<0.05), Mepilex (p<0.0001), Optifoam (p<0.0001) and Tegaderm Alginate Ag (p<0.05), but statistically indistinguishable from Maxorb II Ag or Mepitel Ag. Conclusions Of the SCWDs tested, Acticoat Flex-3 demonstrated the most robust antimicrobial effect. Herein we show that Acticoat Flex-3 may provide the most wound protection against bacterial infection. In conclusion, these data provide clinicians with additional independent evidence to inform their clinical practice on the use of specific wound dressings. PRECIS The antimicrobial properties of Acticoat Flex-3, a dressing composed of nanocrystalline silver layer of knitted polyester, outperformed other silver-containing dressings against E. coli and S. aureus.