Effects of potentiated chlorhexidine on bacteria and tarsocrural joints in ponies.

This study examines how chlorhexidine diacetate (CHD) combined with EDTA and Tris buffer (termed EDTA-Tris) impacts different bacteria and the tarsocrural joints in ponies. The research showed that at a concentration of 0.0005%, the potentiated CHD killed 90% of all the bacteria tested without damaging the pony’s joint tissues.

Research Methods

• Six adult ponies were involved in this study. Their tarsocrural joints were lavaged — or washed out — with either a control solution of 1L phosphate-buffered saline, or with the test solution (1L of 0.0005% CHD in EDTA-Tris).
• The researchers used serial dilutions of CHD alone, CHD in EDTA-Tris, and EDTA-Tris alone to evaluate their bactericidal activity against three types of bacteria: Staphylococcus aureus, Escherichia coli, and Streptococcus zooepidemicus.
• Synovial fluid from the ponies was collected before the lavage procedure and on days 1, 4, and 8 afterwards. On the eighth day, when the ponies were euthanized, samples of their synovia, cartilage, and bone with cartilage were collected.

Results

• The results showed that 0.0005% CHD in EDTA-Tris was 90% lethal to all bacteria they tested. This in vitro result supported the bactericidal properties of the potentiated CHD solution.
• Analysis of the synovial fluid, glycosaminoglycan analysis, and histologic examination of the synovial membrane and articular cartilage showed that washing the pony’s tarsocrural joint with the 0.0005% CHD in EDTA-Tris solution did not negatively affect the synovium or the articular cartilage. The researchers concluded that any changes they observed were due to the lavage process itself, the phosphate-buffered saline solution used as a control, or hemarthrosis (blood in a joint).

Conclusion

• Based on their results, the researchers concluded that a 0.0005% concentration of CHD, when potentiated with EDTA-Tris, was simultaneously bactericidal and safe for the ponies’ joints. They recommend that this solution’s effectiveness as a treatment for infectious arthritis should be evaluated in clinical patients.