Ability of a Concentrated Surfactant Wound Gel Containing PHMB to Prevent Biofilm Formation

Background: Biofilms are formed when microbial cells adhere to a surface and each other and secrete extracellular polymeric substance (EPS), encasing themselves in a matrix. There is increasing evidence showing an association of biofilm formation in wounds and delayed wound healing. Biofilms often show tolerance to antimicrobials and antibiotics and are therefore difficult to treat once formed.

Purpose: The aim of this study was to investigate the ability of a concentrated surfactant gel (CSG) with and without PHMB and a wound gel containing benzalkonium chloride (WG-BC) to prevent biofilm formation.

Methods: Centres for Disease Control (CDC) Bioreactor coupons were placed into 12 well plates, coated with 4g of each wound gel and inoculated with Pseudomonas aeruginosa ATCC 15442. Plates were incubated at 37C for 24 hours. The following day, coupons were transferred to neutralising broth and sonicated for 30 minutes. Samples were serial diluted and plated onto TSA.

Results: The CSG, CSG-PHMB and WG-BC prevented biofilm formation, reducing P. aeruginosa biofilm by 2, 4.5 and 4 log in comparison to an uncoated control.

Conclusion: The antimicrobial gels included in this study significantly reduced biofilm density on coupons over 24 hours, showing the ability to prevent biofilm formation on surfaces coated with it.