Clinical significance of aerobic bacterial flora of the uterus, vagina, vestibule, and clitoral fossa of clinically normal mares.

This study examined the presence and quantity of bacteria in different areas of the reproductive tract in healthy mares. The findings suggest that small amounts of nonpathogenic bacteria are present in the uterus. Also, higher amounts of bacteria were found in the vestibule and clitoral fossa, including certain pathogenic species like Streptococcus zooepidemicus and Escherichia coli.

Research Methodology and Participants

• The study involved 48 mares with no prior reproductive issues or abnormalities in their reproductive tracts. Mostly, these mares were Thoroughbreds and Standardbreds.
• Bacterial swab specimens were collected from four different sites in the reproductive tract, namely the uterus, vagina, vestibule, and clitoral fossa. The latter two areas are part of the external genital tract, while the former are internal.
• The researchers used a sterile speculum for taking vaginal swabs and a double-guarded, occluded culture instrument to collect uterine swabs. This technique ensured the contamination was kept to a minimum during sample collection.

Results and Findings

• The results showed bacterial growth from 31% of the uterine samples and 42% of the vaginal samples. However, out of these, only a small percentage showed more than 10 bacterial colonies after culture.
• Contrastingly, higher bacterial growth was observed in the vestibular (44%) and clitoral fossa (94%) samples. These areas showed moderate to heavy bacterial colony growth in the cultures.
• The cultures from clitoral fossa and vestibular samples also exhibited potential pathogenic bacteria – Streptococcus zooepidemicus and Escherichia coli. However, none of the uterine or vaginal swab specimens displayed such potential pathogens.

Implications and Recommendations

• The study’s findings suggest that even in a healthy mare, the uterus tends to harbor between 1 to 10 colonies of nonpathogenic bacteria. This corresponds to the usage of double-guarded swabbing techniques.
• According to the findings, it is recommended that current prebreeding culture requirements be revised to accommodate the presence of a few nonpathogenic bacterial colonies in healthy mares.
• The researchers also noted that the vulvovaginal fold could play a crucial role as a primary barrier against bacterial contamination ascending into the reproductive tract. This contention stands in contrast to the widely held view that the cervix acts as the main barrier.