Comparative efficacy of three antiseptics as surgical skin preparations in dogs

Abstract

To determine the difference in antimicrobial efficacy between the combination of 2% chlorhexidine and 70% ethanol (CG+A), F10® Skin Prep Solution (F10) and electrochemically activated water (EAW) when used as a surgical preparation in canine patients. Study design Prospective randomised clinical study. Sample population One hundred and seventeen dogs. Materials and methods Skin samples using replicating organism detection and counting plates were taken at four different perioperative sites and time intervals. The first sample of each dog was taken after skin preparation, using a neutral detergent, from the caudal and central aspect of the surgical field. The second sample was taken from the umbilical area following antisepsis with one of the three chosen antiseptics. The third sample was taken from the cranial surgical field two hours after the second sample and the fourth sample was taken from the right para-median aspect of the surgical field, halfway along the incision site at the end of surgery. The colony forming unit (CFU) counts from each sample were quantified according to the level of bacterial contamination. No contamination was defined as zero CFU’s. Low contamination was defined as between 1-12 CFU’s and high contamination was defined as greater than or equal to 13 CFU’s. The three antiseptics were compared with respect to the level of contamination. The manufacturers' directions for use were not followed for any of the skin preparation solutions used in this research project. Results There was no significant difference in the level of contamination between the antiseptics at the first sampling time (P=.454). However, the level of contamination for CG+A was significantly lower compared to F10 and EAW at the second, third and fourth sampling times (P=.001, P=.01, P=.02). Relative to CG+A, EAW had a 7 fold increased risk for bacterial contamination (P=.001) and similarly F10® showed a 10 fold increased risk (P=.001) at the second sampling time for a clean (0 CFU’s) or contaminated (≥ 1 CFU’s) outcome. Similar results were obtained at the third and fourth sampling times when EAW had a 3 and 4 fold increased risk for bacterial contamination (P=.015) respectively and F10 showed a 5 and 4 fold increased risk (P=.001). Conclusion The combination of 2% chlorhexidine and 70% alcohol was a statistically significant more effective skin antiseptic at achieving a zero CFU count and low levels of contamination when compared to F10 and EAW for surgical preparation in dogs undergoing ovariohysterectomy