EFFECTS OF POTENTIATED CHLORHEXIDINE ON BACTERIA AND TARSOCRURAL JOINTS IN PONIES

Objectives-To evaluate the bactericidal properties of chlorhexidine di acetate (CHD) after potentiation with EDTA and Tris buffer (EDTA-Tris) , and to find a potentiated CHD concentration that would achieve 90 to 100% killing for ail bacteria tested. Animals-6 adult ponies. Procedu re-Serial dilutions of CHD, CHD in EDTA-Tris, and EDTA-Tris alone were evaluated for bactericidal activity against Staphylococcus aureus, Es cherichia cell, and Streptococcus zooepidemicus. The tarsocrural joint s of 6 ponies were ravaged with either 1 L of phosphate-buffered salin e solution (control) or 1 L of 0.0005% CHD in EDTA-Tris. Synovial flui d was collected before lavage and on days 1, 4, and 8. Synovia, cartil age, and bone with cartilage were collected on day 8 when the ponies w ere euthanatized. Results-In vitro results indicated that 0.0005% CHD in EDTA-Tris was 90% lethal to all bacteria tested. Results of synovia l fluid analysis, glycosaminoglycan analysis, and histologic examinati on of the synovial membrane and articular cartilage indicated that joi nt lavage with 0.0005% CHD in EDTA-Tris was not detrimental to the syn ovium or the articular cartilage of pony tarsocrural joints. Changes o bserved were a result of the actual lavage process, the phosphate-buff ered saline solution, and hemarthrosis. Conclusions-A concentration of 0.0005% CHD in EDTA-Tris was 90% lethal to ail bacteria tested. Pony tarsocrural joint lavage with 0.0005% CHD in EDTA-Tris was not detrime ntal to the synovium or the articular cartilage. The efficacy of 0.000 5% CHD potentiated with EDTA-Tris as a potential joint lavage fluid fo r treatment of infectious arthritis needs to be evaluated in clinical patients.