Effects of topical application of silver sulfadiazine cream, triple antimicrobial ointment, or hyperosmolar nanoemulsion on wound healing, bacterial load, and exuberant granulation tissue formation in bandaged full-thickness equine skin wounds.

The researchers investigated the effects of three different topical treatments on wound healing in horses. They found that none of the treatments significantly sped up the process compared to an untreated control, but the triple antimicrobial ointment (TAO) seemed to limit the formation of excessive granulation tissue.

Research Design and Methods

• The researchers selected eight healthy adult horses and created a 2.5 × 2.5-cm, full-thickness, cutaneous wound on the dorsal aspect of each metacarpus and metatarsus.
• The wounds were subsequently bandaged and inoculated with bacteria and fungi the following day.
• Each wound on a given horse was randomly assigned to one of four treatment groups: 1% silver sulfadiazine cream (SSC), triple antimicrobial ointment (TAO), hyperosmolar nanoemulsion (HNE), or no topical treatment (the control group).
• The team performed bandage changes, culture of wound samples, treatments, photography for wound measurements, and biopsies at predetermined time points.
• They compared the time until wound closure, the number of exuberant granulation tissue (EGT) excisions, microbial counts, and scores for selected histological characteristics among the groups.

Results

• The median time to wound closure across all groups was 42 days, indicating that none of the treatments led to a significant decrease in healing time.
• There were no differences among the groups regarding the histologic characteristics of the wound healing process.
• Of note, microbial counts were significantly higher for wounds treated with HNE on days 9 and 21, compared with wounds treated with SSC and TAO, but not when compared to the control group.
• The SSC and HNE treatment groups had a higher proportion of wounds needing EGT excision compared to the TAO group, suggesting TAO has a preventive effect on EGT formation.

Conclusions and Clinical Relevance

• The treatments investigated in this study did not result in faster wound closure compared to untreated wounds. However, TAO seems to limit the formation of EGT, which could make it a suitable treatment choice when intervention is deemed necessary.