Evaluation of the Biofilm Prevention and Disinfection Capabilities of Topical Wound Treatments

There are a number of topical wound coverings that claim to be effective in treating or preventing bacterial infections and biofilms within the wounds. This work has been undertaken to determine the capability of these products to inhibit and/or disinfect already resident biofilms. The products evaluated in this testing include silver dressings, collagenase, fish skin, and biofilm disruption technology. Empty cells, gauze, and saline were used as controls for enumeration. 

Biofilm inhibition has been evaluated using a mixed-species colony drip flow reactor model (DFR) model against Staphylococcus aureus and Pseudomonas aeruginosa growth. In this testing, biofilms were grown on the test substance or controls for 24 hours using a 10% BHI solution with inoculum at 33C. Biofilm growth was determined by serial dilution and plating. Inhibition was determined by subtraction from controls. In addition, staining with Syto-9 and wheat germ agglutin followed by confocal microscopy was used to visualize the biomass prevention produced by each of the treatments.

Biofilm disinfection was evaluated using a modified version of the ASTM E2647-08 the Drip Flow Reactor model against mixed species biofilms of S. aureus and P. aeruginosa. Biofilms were grown on hydroxyapatite coated slides for three days prior to treatment. The treatments were applied for 24 hours with saline used as a control treatment. The remaining biofilm was determined by serial dilution and plating. Biofilm disinfection was determined by subtraction from controls.