Streptomycin-resistant Escherichia coli as a marker of vulvovestibular contamination of endometrial culture swabs in the mare.

The study explores how contamination from the vulvovestibular area impacts endometrial culture swabs in mares, utilizing a streptomycin-resistant strain of E. coli as a marker. It finds that even with thorough cleansing of the perineal area before swabbing and choosing a vaginal speculum approach for swabbing, complete exclusion of vulvovestibular contamination is not possible, however, contamination can be significantly reduced.

Introduction

• The research focuses on understanding the impact of vulvovestibular contamination on the results of endometrial culture swabs in mares, a significant aspect of reproductive health management in horses.
• A streptomycin-resistant strain of E. coli was used as a marker. This bacterium was applied to the vulvovestibular area of the mares before swabbing commenced.

Methodology

• The perineal area of the mares was initially cleansed with soap and water, then dried before any swabbing was done.
• Endometrial culture swabs were collected from mares that were in varying stages of their reproductive cycle: anestrus, diestrus, and estrus.
• Two different approaches were used for swabbing: manual transvaginal swabbing and vaginal speculum swabbing.

Findings

• In the manual transvaginal swabbing method, 22 of the 24 endometrial swabs from 12 mares were found to be contaminated with the experimental E. coli strain, with only one swab yielding more than nine colonies of the bacterium.
• When the vaginal speculum approach was used, fewer swabs – specifically, three out of 12 from 12 mares – showed contamination, yielding between one and three colonies.
• The stage of the reproductive cycle did not have an effect on the extent of swab contamination.
• Swabbing via a vaginal speculum resulted in a significantly smaller proportion of positive cultures compared to the manual transvaginal method.

Conclusion

• Although continued contamination of the endometrial swabs from the vulvovestibular region could not be entirely eliminated, contamination could be significantly reduced.
• If the perineal area is properly cleansed prior to swabbing, even after a thorough contamination with a broth culture, it can be expected that fewer than ten bacterial colonies will be present.
• The study emphasizes that the method of swabbing and the prior cleaning of the perineal area play a significant role in reducing vulvovestibular contamination of endometrial swabs in mares.