In-situ characterization of the bacterial biofilm associated with Xeroform™ and Kaltostat™ dressings and evaluation of their effectiveness on thin skin engraftment donor sites in burn patients.

Biofilm forms when bacteria surrounded by an extracellular matrix aggregate on a surface. It can develop on many surfaces, including wound dressings; this can be particularly nefarious for burn patients undergoing skin grafting (autograft) for burn wound coverage as they often suffer from compromised immune system function. Autograft donor sites are particularly vulnerable to biofilm formation; as such, timely healing of these sites is essential. Our aim was to apply scanning electron microscopy to compare the efficacy of two types of wound dressings in preventing the formation of bacterial biofilm on burn patient skin graft donor sites. One dressing contained bismuth tribromophenate at a concentration of 3% which confers it bacteriostatic properties (Xeroform™). The other was an absorptive alginate calcium sodium dressing (Kaltostat™). Samples of each wound dressing, which were in contact with the skin graft donor site, were prepared for analysis under the scanning electron microscope (SEM) using an original method developed by our research group that aims to maintain the integrity of the biofilm microstructure. Samples prepared by this method were then analyzed using SEM, which allowed the characterization of biofilm and the evaluation of bacterial density on the studied dressing samples. To this day, this imaging technique has been rarely employed for dressing analysis and this is the first time that it is employed for in situ biofilm visualization for this particular application.