Accumulation of amikacin in synovial fluid after regional limb perfusion of amikacin sulfate alone and in combination with ticarcillin/clavulanate in horses.

The researchers of this article have conducted an experiment to determine the impact of regional limb perfusion (RLP) using the antibiotic amikacin sulfate, either alone or in combination with ticarcillin/clavulanate, on the concentration and antimicrobial activity of amikacin in the synovial fluid in horses. The results indicate that using the antibiotic combination results in a significantly lower concentration of amikacin and reduced antimicrobial activity against certain types of bacteria.

Research methodology

• The researchers conducted their experiment on sedated, standing horses in order to closely mimic typical veterinary practices.
• The process of regional limb perfusion (RLP) was used where the antibiotics were directly injected into the horse’s limb with a tourniquet placed at mid-antebrachium to contain the drugs within the limb.
• Two groups were studied – one received amikacin sulfate alone (Group A) and another group received a combination of amikacin sulfate and ticarcillin/clavulanate (Group AT).
• Several types of fluid and blood samples were collected from various points immediately after injection, before tourniquet release and at timed intervals post tourniquet release.

Findings

• The concentration of amikacin in the synovial fluid of the middle carpal joint was significantly lower in Group AT compared to Group A, both at 30 minutes and 60 minutes after tourniquet release.
• This lower concentration of amikacin in Group AT was associated with significantly reduced zones of inhibition for Klebsiella pneumoniae resistant to ticarcillin, showing the decreased antimicrobial activity in the antibiotic combination group.

Conclusion

• The main takeaway from this research is that the combination of amikacin and ticarcillin/clavulanate used in regional limb perfusion results in a much lower concentration of the antibiotic amikacin in the synovial fluid of horses.
• This lower concentration is associated with reduced antimicrobial activity against a range of bacterial strains, including Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa.
• This research suggests that using amikacin alone may be more effective for treating infections in horses, although further studies would be needed to confirm this and to determine the implications for veterinary treatment strategies.