Evaluation of skin bacterial flora before and after aseptic preparation of clipped and nonclipped arthrocentesis sites in horses.

The research examines if hair removal from horses’ joints affects the efficacy of antiseptics in reducing bacterial growth when preparing for an arthrocentesis procedure.

Methodology

The following steps were undertaken in the research:

• The study involved twelve adult horses. The hair above one midcarpal joint (wrist joint) and one distal interphalangeal joint (joint at the base of the tail) of each horse were clipped. The corresponding joint on the opposite side was left unclipped, acting as a control.
• A pre-scrub sample for a microbial culture was taken from the dorsal surface of all four joints for each horse, providing an initial reading of the bacterial colonies present.
• Each site was then prepared aseptically with povidone iodine and 70% alcohol, and a second sample was collected for microbial culture to determine the number of colony forming units (CFUs) remaining.
• The number of CFUs was recorded for each sample 24 hours after the inoculation of blood agar plates.

Results

The findings of the research were as follows:

• No significant difference was found in the number of post-scrub CFUs between the clipped and non-clipped regions around the midcarpal or distal interphalangeal joints, indicating that hair presence did not impede the effectiveness of antiseptic preparation.
• However, bacterial reduction after aseptic preparation was significantly higher in clipped regions (99.8%) than in non-clipped regions (96.2%) for the midcarpal joint. The difference was not significant for the distal interphalangeal joint.
• Interestingly, a significant difference was found in the number of prescrub CFUs between clipped and non-clipped regions for the midcarpal joint, but not for the distal interphalangeal joint.
• Post-scrub samples from both clipped and non-clipped areas cultured Bacillus sp, nonhemolytic Staphylococcus sp, and Micrococcus sp.

Conclusions

The study concludes that the presence of hair over the midcarpal and distal interphalangeal joints does not prevent antiseptics from effectively reducing bacterial flora to a safe level for performing an arthrocentesis. Therefore, aseptic preparation of these joints can be done without clipping the horse’s hair.