Histologic changes and gene expression patterns in biopsy specimens from bacteria-inoculated and noninoculated excisional body and limb wounds in horses healing by second intention

Biofilm and Equine Limb Wounds

Simple Summary

Delayed wound healing commonly occurs in limb wounds of horses. These equine limb wounds share many similarities with chronic wounds in humans and one of them seems to be the presence of biofilm, even though equine wound biofilm research is just emerging. Biofilms are aggregates of bacteria, and within these aggregates, the bacteria are protected from both antimicrobial substances and the immune response of the host. Biofilm infections in wounds often delay healing and are impossible to detect with routine diagnostics. However, if suspected, aggressive treatment is needed and includes physically removing biofilm and unhealthy tissue from the wound during debridement and immediately applying antimicrobial compounds to kill any biofilm or bacteria not removed during debridement.

Abstract

In chronic wounds in humans, biofilm formation and wound chronicity are linked, as biofilms contribute to chronic inflammation and delayed healing. Biofilms are aggregates of bacteria, and living as biofilms is the default mode of bacterial life; within these aggregates, the bacteria are protected from both antimicrobial substances and the immune response of the host. In horses, delayed healing is more commonly seen in limb wounds than body wounds. Chronic inflammation and hypoxia are the main characteristics of delayed wound healing in equine limbs, and biofilms might also contribute to this healing pattern in horses. However, biofilm formation in equine wounds has been studied to a very limited degree. Biofilms have been detected in equine traumatic wounds, and recent experimental models have shown that biofilms protract the healing of equine limb wounds. Detection of biofilms within wounds necessitates advanced techniques that are not available in routine diagnostic yet. However, infections with biofilm should be suspected in equine limb wounds not healing as expected, as they are in human wounds. Treatment should be based on repeated debridement and application of topical antimicrobial therapy.