Biofilm and Equine Limb Wounds

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.

Infectious Uveitis in Horses and New Insights in Its Leptospiral Biofilm-Related Pathogenesis

“…Other biofilm-associated diseases include wound infections [496,497], infected implants and bone sequestrum formation [498], osteomyelitis [499][500][501], chronic otitis [449,502], infectious endocarditis [503], and borreliosis [504][505][506]. Whenever possible, mechanical or surgical removal of the biofilm is considered the most effective therapy to eliminate the infection [481,507,508].…”

Microbial Biofilms in Veterinary Medicine

“…In humans, microbial biofilms related to wound infections lead to chronic inflammation and delayed management (30). Although there are many biofilm-related researches conducted in animal models including rodents, rabbits, pigs, dogs, horses, etc., limited studies have been directly carried out for the determination of the clinical importance of microbial biofilms in the field of veterinary medicine.…”

“…They form aggregates and microcolonies, differentiate by the production of extracellular matrix (iii), and finally, the maturation of biofilms occurs by the attachment of additional microorganisms (iv) (Figure 1). The matrix consists of extracellular polymeric compounds including polysaccharides, proteins, DNA, and lipids, and protects the bacteria from extreme and depleted environments and antimicrobials, and gives mechanical stability (30,43). Within biofilms, bacterial cells are sheltered against different adverse environmental conditions such as ultraviolet light radiation, osmotic changes, pH variability, dehydration, antimicrobial drugs, disinfectants, and host immune responses (40).…”

Wound swabs versus biopsies to detect methicillin resistant Staphylococcus aureus in experimental equine wounds

“…Distal limb wounds of horses continue to be a source of frustration for equine owners and practitioners due to the well described complications of equine wound healing. Wound‐healing complications are often attributed to physiologic characteristics of the distal limbs, including reduced vascularity and temperature, and low‐grade chronic inflammation 1–4 . These challenges result in chronic, nonhealing wounds that can be further compromised by bacterial infections, including antimicrobial resistant (AMR) bacteria 5–11 .…”

“…Wound-healing complications are often attributed to physiologic characteristics of the distal limbs, including reduced vascularity and temperature, and low-grade chronic inflammation. [1][2][3][4] These challenges result in chronic, nonhealing wounds that can be further compromised by bacterial infections, including antimicrobial resistant (AMR) bacteria. [5][6][7][8][9][10][11] Methicillin-resistant Staphylococcus aureus (MRSA) is present in the equine population, and horse-tohuman transmission of AMR bacteria has been reported.…”