Effectiveness of a non-medicated wound dressing on attached and biofilm encased bacteria: laboratory and clinical evidence.

Objective: The objective of this study was to evaluate the ability of a non medicated, hydro-responsive wound dressing (HRWD) to effectively aid in the removal of bacteria known to reside (and cause infections) within the wound environment.
Method: A series of in vitro studies were undertaken using Staphylococcus aureus and Pseudomonas aeruginosa biofilms to evaluate the capabilities of the HRWD to disrupt and disperse biofilms.
Results: Biofilms can be broken up and dispersed by HRWD and both Staphylococcus aureus and Pseudomonas aeruginosa numbers can be reduced by a greater than log ₂ reduction in the presence of HRWD. However, no 'active' agents are released into the wound environment that have an antimicrobial effect.
Conclusion: Overall, these studies have shown that this dressing acts as an effective debridement tool, and there are other 'physical' antimicrobial mechanisms impacting bacterial residence. These mechanisms include 1) breaking up and dispersal of biofilms so that the resultant planktonic bacteria are absorbed by the dressing and then 2) sequestered and retained (trapped) within its matrix. Additionally, when PHMB (polyhexamethylene biguanide) is bound within the dressing core but is not released into the wound environment there is the added antimicrobial effect resulting from 3) physical contact with this antiseptic component. Reducing the pathogenicity of the bacteria still further is the dressings ability to 4) absorb and sequester the damaging proteases released by pathogenic bacteria.