Uptake of PHMB in a bacterial nanocellulose-based wound dressing: A feasible clinical procedure

Background: With the increase of antimicrobial resistance in recent decades, other methods of preventing and fighting infections must be considered. Burn patients, whose wound areas are often extensive, are especially prone to wound infections. The loading of bacterial nanocellulose (BNC) with antiseptics has already been successfully performed but unfortunately, the described procedure is time-consuming and thus not applicable in a clinical emergency setting. Therefore, a clinically feasible approach was established. Material and methods: Sheets of BNC-based wound dressings were placed into antiseptic solutions containing PHMB (Prontosan^® and LAVANID^® 2) and were left to soak for up to two hours. At different time points, samples were analysed for their concentration of PHMB and antiseptic efficacy. Results: Within 30 min, clinically relevant concentrations of PHMB were achieved in the BNC-based wound dressing. The 30-min PHMB uptake for Prontosan^® and LAVANID^® 2 resulted in concentrations of 0.05% and 0.019%, respectively. Samples from the PHMB loaded dressing showed a dose dependent antiseptic efficacy for Staphylococcus aureus. Conclusion: This experiment showed that the loading of BNC-based wound dressings with PHMB-containing antiseptics was achieved by a simple and quick procedure. According to studies a PHMB concentration of 0.001% can already inhibits all bacterial growth, indicating that the concentrations of PHMB in the BNC-based wound dressings after 30 min are higher than the minimal inhibitory concentration and the antiseptic efficacy after 120 min loading analysed by an standardized bacterial disk diffusion assay was shown to be comparable to the clinically used Suprasorb^® X + PHMB wound dressing.