Antibacterial efficacy of an iodine dressing on common wound pathogens and ability to penetrate through layers representative of wound eschar in vitro

Acute wounds such as surgical sites can become colonised with microorganisms leading to infection, increased inflammation and delayed wound healing. Additionally, the wound bed consists of eschar, which is difficult to remove; therefore, dressings are required to penetrate through this to exert an antibacterial effect deeper in the wound bed. The aim of this study was to evaluate the antibacterial efficacy of an iodine dressing with and without a concentrated surfactant gel with antibacterial preservative agents (CSG). Additionally, penetration of the iodine dressing through representative layers of wound eschar in vitro was evaluated.

The antibacterial activity of the iodine dressing with and without a CSG was evaluated against Staphylococcus aureus ATCC 29213 and Pseudomonas aeruginosa ATCC 15442 using the zone of inhibition assay. The ability of the dressings to penetrate through agar, blood and foetal calf serum (FCS) as representative layers of wound eschar was evaluated in vitro in 50 mL Falcon tubes.

The ZOI of the iodine dressing against P. aeruginosa and S. aureus was 3.77 mm and 5.33 mm, respectively. When in combination with the CSG, the ZOI was 7.30 mm and 8.80 mm, respectively showing a significantly greater inhibition than when used alone (p ≤ 0.0003). The iodine dressing demonstrated the ability to penetrate through agar, blood and FCS showing growth inhibition of S. aureus of 3.3 - 7.3 mm (p 0.0367).

The findings in this study have demonstrated antibacterial efficacy of an iodine dressing against two common wound pathogens, S. aureus and P. aeruginosa, which is significantly enhanced when in combination with a CSG. Furthermore, the findings show that the iodine dressing can penetrate through representative layers of wound eschar to exert an antibacterial effect on bacterial cells that may be deeper in the wound bed.

Trademarked Items (if applicable): IoPlex, PluroGel

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