The increased killing of biofilms in vitro by combining topical silver dressings with topical negative pressure in chronic wounds

Chronic wounds remain a significant medical and financial burden in hospitals of today. A major factor in the transition from an acute to a chronic wound is its bacterial bioburden. Developments in molecular techniques have shown that chronic wounds remain colonised by many species of bacteria and that the bacteria within these chronic wounds exist in two forms. Treatments of chronic wounds have maintained a challenging field and significant ongoing research is being conducted. With the development of an in vitro wound model, we applied topical negative pressure (TNP) dressings to a spectrum of common bacterial biofilms found in chronic wounds and studied the synergistic efficacy between the application of TNP and silver-impregnated foam against these biofilms. This synergistic response was seen within the laboratory strains of staphylococcal biofilms over a 3-day treatment period but lost following the 5 days of treatment. However, combining topical pressure dressings and silver foam lead to a synergistic inactivation in Pseudomonas species over both 3-day and 5-day treatments.