Effects of various wound dressings on microbial growth in perfused equine musculocutaneous flaps.

The research compares the effects of various wound dressings on the growth of bacteria in an experimental wound model using equine models. It found that cadexomer iodine dressings were the most effective at reducing bacterial growth.

Methodology and Approach

• The study used abdominal musculocutaneous flaps from 16 equine cadavers (dead horses). Full-thickness skin wounds were developed in each flap.
• The tissues of these wounds were perfused (infused) with a saline solution.
• The wounds were then inoculated with specific bacteria (methicillin-resistant (MRSA) or another bacterium) and covered with various dressings. The dressings used contained constituents like activated charcoal, boric acid, cadexomer iodine, calcium alginate, manuka honey, nanoparticle silver, polyhexamethylene biguanide or a control of nonadherent gauze.

Procedure for Data Collection

• Measurements were taken at baseline (immediately before dressing application) and then at 6, 12, 18, and 24 hours afterward. These measurements were used to determine the mean bacterial load (MBL) in the wounds, evaluating the effectiveness of the microbial growth control by the dressing types.
• The MBLs at each subsequent time point were compared to the baseline within each dressing type, and comparisons were also made between dressing types at each time point.

Results and Findings

• The results showed that MBLs in wounds inoculated with MRSA and covered with cadexomer iodine dressings significantly decreased from the baseline at the 6- and 12-hour points.
• For wounds with different bacteria, MBLs significantly increased from baseline in all wound types at various points, except in wounds covered with cadexomer iodine dressings.
• The MBLs in wounds covered with cadexomer iodine dressings were reported to be lower than all others. However, these results were not always significantly different from those for wounds covered with dressings of boric acid, manuka honey, nanoparticle silver, and polyhexamethylene biguanide.

Conclusions

• It was concluded that, in this experimental wound model, growth of MRSA and another bacteria was most effectively reduced or inhibited by cadexomer iodine dressings.
• The authors suggest that these results and the effect of the dressings on wound healing should be confirmed with in vivo studies (experimental studies within live organism).