Comparison of Chlorhexidine and Alcohol-Based Antisepsis of the Distal Limb of Horses. Doyle AJ1, Saab ME2, Lewis K1, McClure JT1. 1University of Prince Edward Island, Department of Health Management, Charlottetown, PE, Canada; 2University of Prince Edward Island, Diagnostic Services, Charlottetown, PE, Canada.
An alcohol-based rub has been confirmed effective at reducing bacterial counts on equine skin. Skin sites with expected high bacterial burden have not been tested nor has a comparison to a common detergent protocol been performed. Our objective was to determine if ethanol-based antisepsis reduces bacterial counts on the equine distal limb comparable to a current chlorhexidine scrub method and to determine the most effective application technique. Forty-one horses were used in the study and each limb was randomly assigned to a treatment group: 5 min scrub using 4% chlorhexidine gluconate to a clipped site (CHG); 90 s scrub using 80% ethanol to a clipped site (ETC); 90 s contact with 80% ethanol applied as a spray to a clipped site (ETS); and 90 s scrub using 80% ethanol to an unclipped site (ETUC). Samples were collected pre- and posttreatment and plated in duplicate. Bacterial counts were log10 transformed and averaged between duplicates. A linear mixed model was used to compare mean log10 CFU/mL reduction between groups. There was no significant difference in mean log10 CFU/mL reduction between CHG and ETC in either forelimbs or hindlimbs. In forelimbs, there was no significant difference in mean log10 CFU/mL reduction between any groups. In hindlimbs, CHG had significantly greater mean log10 CFU/mL reduction than ETUC and ETS. The main limitation of the study was that researchers were not blinded to treatment groups during sample collection. This study showed no difference between CHG and ET groups.