Ability of an iodine dressing to prevent biofilm formation of common wound pathogens Pseudomonas aeruginosa and Staphylococcus aureus
Infection through colonisation of medical devices or acute wounds can lead to biofilm formation, delayed wound healing and development of chronic wounds. Biofilms are difficult to treat due to increased recalcitrance to antibacterial agents; therefore, dressings that can prevent the formation of biofilms are preferable. The aim of this study was to evaluate the biofilm prevention ability of an iodine dressing in comparison to other antimicrobial based dressings.
Biofilm prevention of Pseudomonas aeruginosa and Staphylococcus aureus was evaluated over 24 hours on glass coupons in the drip flow bioreactor model and on CDC coupons, respectively. Any formed biofilm was recovered from both models and samples were serial diluted and plated onto Tryptone Soya agar (TSA). Plates were incubated at 37°C overnight and the following day colonies enumerated. The sequestering ability of the dressings was also investigated using 2 models. Dressings were placed into 12-well culture inserts, placed onto TSA and inoculated with P. aeruginosa. For the second model, dressings were placed into a 30 mL syringe, inoculated with P. aeruginosa, and supplied with 270 mg/L TSB at a rate of 5 mL/hour/syringe.
Following a 24-hour challenge period, no biofilm had formed on the coupons wrapped in the iodine dressing in both models. In comparison, the untreated control coupons had a P. aeruginosa and S. aureus biofilm cell density of 1.87 x 108 CFU/mL and 9.1 x 107 CFU/mL, respectively showing significant ability to prevention biofilm formation (p ≤ 0.0212). The models evaluating sequestering ability of the dressings showed no dissemination of P. aeruginosa from the iodine dressing over 72 hours.
The findings in this study show the iodine dressing has the capability of preventing biofilm formation by sequestering the bacteria, preventing dissemination of it and by acting as a barrier preventing formation on the surface it is covering.      
Trademarked Items (if applicable): Ioplex
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