Silver antimicrobial dressings in wound management: A comparison of antibacterial, physical, and chemical characteristics

Silver-containing dressings are widely used to assist with management of infected wounds and those at risk of infection. However, such dressings have varied responses in clinical use due to technological differences in the nature of their silver content and release and in properties of the dressings themselves. This study examines the relationship between silver content, rate of silver release, and antibacterial activity in a simulated wound fluid model against Staphylococcus aureus and Pseudomonas aeruginosa. The study also looks at other important measures for the clinical performance of dressings including fluid-handling properties and dressing pH. Seven proprietary silver-containing dressings (AQUACEL (R) Ag [Hydrofiber (R); "nonwoven A"], Acticoat (TM) Absorbent [alginate; "nonwoven B"], SILVERCEL (TM) [alginate-carboxymethylcellulose nylon blended fibers; "nonwoven C"], Contreet (R) Foam [nonadhesive; "foam A"], PolyMem (R) Silver ["foam B"], Urgotul (R) S.Ag ["gauze"], and SilvaSorb (R) ["hydrogel"]) were assessed. No direct correlation between silver content, silver release, and antibacterial activity was found. Dressings-with the highest silver content were nonwoven B and nonwoven C, while the lowest levels were found in nonwoven A and hydrogel. Nonwoven A, gauze, and nonwoven B were most effective against S. aureus and P. aeruginosa;. however, their silver release rates differed widely. Free fluid absorption was greatest for the 2 foam dressings and least for gauze. However, nonwoven A and nonwoven B showed the best fluid retention under conditions of compression, while nonwoven A demonstrated the lowest level of capillary wicking. Dressing choice is a vital part of the successful management of infected wounds and those wounds at risk for infection. This study suggests that dressing selection should be based on the overall properties of the dressing clinically relevant to the wound type and condition.