Effects of potentiated chlorhexidine on bacteria and tarsocrural joints in ponies.
OBJECTIVE
To evaluate the bactericidal properties of chlorhexidine diacetate (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 all bacteria tested.


METHODS
6 adult ponies.


METHODS
Serial dilutions of CHD, CHD in EDTA-Tris and EDTA-Tris alone were evaluated for bactericidal activity against Staphylococcus aureus, Escherichia coli, and Streptococcus zooepidemicus. The tarsocrural joints of 6 ponies were lavaged with either 1 L phosphate-buffered saline solution (control) or 1 L of 0.0005% CHD in EDTA-Tris. Synovial fluid was collected before lavage and on days 1,4, and 8. Synovia, cartilage, and bone with cartilage were collected on day 8 when the ponies were euthanatized.


RESULTS
In vitro results indicated that 0.0005% CHD in EDTA-Tris was 90% lethal to all bacteria tested. Results of synovial fluid analysis, glycosaminoglycan analysis, and histologic examination of the synovial membrane and articular cartilage indicated that joint lavage with 0.0005% CHD in EDTA-Tris was not detrimental to the synovium or the articular cartilage of pony tarsocrural joints. Changes observed were a result of the actual lavage process, the phosphate-buffered saline solution, and hemarthrosis.


CONCLUSIONS
A concentration of 0.0005% CHD in EDTA-Tris was 90% lethal to all bacteria tested. Pony tarsocrural joint lavage with 0.0005% CHD in EDTA-Tris was not detrimental to the synovium or the articular cartilage. The efficacy of 0.0005% CHD potentiated with EDTA-Tris as a potential joint lavage fluid for treatment of infectious arthritis needs to be evaluated in clinical patients.
Klohnen
A
A
Comparative Orthopedic Research Laboratory, School of Veterinary Medicine, University of Wisconsin, Madison 53706, USA.
Wilson
D G
DG
Hendrickson
D A
DA
Cooley
A J
AJ
MacWilliams
P S
PS
D000818:Animals; D000891:Anti-Infective Agents, Local / Q000494:pharmacology* / Q000627:therapeutic use; D001170:Arthritis, Infectious / Q000188:drug therapy / Q000662:veterinary; D001419:Bacteria / Q000187:drug effects*; D018407:Bacterial Physiological Phenomena; D001707:Biopsy, Needle / Q000379:methods / Q000662:veterinary; D002021:Buffers; D002358:Cartilage, Articular / Q000737:chemistry / Q000382:microbiology; D002710:Chlorhexidine / Q000494:pharmacology* / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D004492:Edetic Acid; D004926:Escherichia coli / Q000187:drug effects / Q000502:physiology; D006025:Glycosaminoglycans / Q000032:analysis; D006734:Horse Diseases / Q000188:drug therapy; D006736:Horses / Q000382:microbiology*; D007596:Joints / Q000737:chemistry / Q000382:microbiology*; D007958:Leukocyte Count / Q000662:veterinary; D013211:Staphylococcus aureus / Q000187:drug effects / Q000502:physiology; D018502:Streptococcus equi / Q000187:drug effects / Q000502:physiology; D013582:Synovial Fluid / Q000382:microbiology; D013583:Synovial Membrane / Q000737:chemistry / Q000382:microbiology; D013643:Tarsus, Animal / Q000382:microbiology* / Q000473:pathology; D014325:Tromethamine
D000891:Anti-Infective Agents, Local; D002021:Buffers; D006025:Glycosaminoglycans; D014325:Tromethamine; D004492:Edetic Acid; D002710:Chlorhexidine