Assessing the Antimicrobial Performance of a Novel Non-Woven PHMB Dressing, Over a 21-Day Period

Introduction: A new, high gelling fibre dressing combining Carboxymethyl Cellulose (CMC) and polyhexamethylene biguanide (PHMB) has been developed for use on acute and chronic wounds. The dressing currently exhibits fast and sustained antimicrobial performance against a range of common wound isolates, within 7 days, based on log reduction testing. The ability of the dressing to remain efficacious over an extended wear-time i.e. 21 days requires investigating due to its importance both clinically to the patient and with regards to associated cost implications. In addition the absorbency and elution profile of the product will be assessed for the extended time period as they are also key attributes to the dressing performance.

Method: The sustained antimicrobial activity was performed in accordance with AATCC TM-100 guidelines over a 21-day period against a wide range of microorganisms associated with chronic wounds. Dressings were treated with simulated wound fluid prior to inoculation to replicate soiled wound conditions and repeat challenge of each microorganism was administered at intervals, throughout the test period.Standardised test methods were utilised to analyse absorbency and elution over 21 days.

Results: The data demonstrates the test device to provide sustained and highly efficacious antimicrobial performance over the 21 day test period, under conditions of clinical use.

Discussion: The in vitro testing has allowed for the extended antimicrobial performance of the dressing to be evaluated and the results achieved demonstrate that the product can provide excellent antimicrobial efficacy over 21 days. The ability of a dressing to maintain its antimicrobial capabilities over a longer period may significantly minimize the need for multiple dressing changes, a priority when dealing with burns patients as dressing changes can be painful when taking into account that superficial partial- and deep partial-thickness burns can take at least 3 weeks to heal.