Activity of a New Silver-Containing Gelling Fibre Dressing Against Biofilm (in vitro)

Microbial infection is a significant problem in chronic wounds and the presence of bacterial biofilm is a major reason for impaired healing (Høiby et al. 2015). The lower sensitivity to antimicrobials of biofilm bacteria, relative to that of planktonic bacteria, needs to be considered when developing new management strategies for wounds colonised by biofilm. This study aimed to evaluate and compare the susceptibility of biofilm to silver sulfate, to that of planktonic bacteria, using a 3D in vitro model mimicking soft tissue biofilm infection (Werthén et al. 2010, illustrated in Figure 1) and a minimal bactericidal concentration (MBC) model. The new silver-containing gelling fibre dressing reduced the bioburden by greater than five logarithmic units relative to the control after 24 hours of treatment time. The data indicate that silver, without the addition of other actives, is sufficient to reduce the bioburden of biofilms. However, this is dependent on the type of dressing as the results of this study indicate that not all silver-containing dressings perform equally.