Influence of intravenous regional limb perfusion with amikacin sulfate on Staphylococcus aureus bioburden in distal limb wounds in horses.

This research investigated the impact of a technique called intravenous regional limb perfusion (IVRLP) with amikacin on the bacterial load, specifically Staphylococcus aureus, in lower limb wounds in horses. The study found that this method did not significantly affect the bacterial levels in the wounds.

Methodology

• The researchers used four adult horses for this experimental study.
• Comprehensive thickness wounds were created on the dorsal part of each horse’s front leg and infected with the bacterium Staphylococcus aureus.
• One front leg of each horse was randomly selected to receive IVRLP treatment with amikacin (a type of antibiotic) on the 2nd, 3rd, and 4th days after wounding.
• Tissue biopsies were taken on days 2, 5, and 8 and cultured to measure the bacteria population in the wounds.
• Two of the horses underwent the experiment again in a crossover design where the other leg was subjected to IVRLP.
• In the closing stages of the study, IVRLP was performed on both front legs of three horses; the legs were infused with new methylene blue in a volume equal to the amikacin dose. This was done to visualize and assess the dispersion of the drug.

Results

• Measurements of bacterial bioburden showed no significant difference between the control and IVRLP-treated legs, either collectively or at any particular time.
• The frequency of detectable bacterial growth also showed no difference between the control and treated groups.
• In terms of visualization with methylene blue, all tissues showed the dye following IVRLP through the palmar digital vein, but the dye was not seen in legs that received infusion through the cephalic vein.

Conclusion

• The study concludes that IVRLP may not efficiently concentrate amikacin within a wound, and it did not influence the Staphylococcus aureus bioburden in experimentally created wound infections.
• Although this method appeared not to have the desired effect on reducing bacterial presence in the wounds, it’s an important finding for future research and current veterinary practice.