Fungal endometritis in broodmares: clinical presentation, prevalence in Ireland and diagnostic performance of cytology.

Fungal endometritis is a rare uterine infection in broodmares linked to reduced fertility, and this study investigated its clinical features, prevalence in Ireland, the types of fungi involved, and the effectiveness of cytology as a diagnostic tool.

Study Objectives and Design

• To describe 11 clinical cases of fungal endometritis in broodmares, including their medical history, clinical signs, treatment, and outcomes.
• To analyze the prevalence trends of fungal endometritis in Ireland from 2019 to 2024 using a large dataset of uterine samples.
• To examine the types of fungal species isolated from diagnostic uterine samples.
• To evaluate how well cytology detects fungal endometritis by comparing it to culture results.

Study 1: Clinical Case Review

• Reviewed medical records of 11 mares diagnosed with fungal endometritis.
• All mares had a history of prior antimicrobial treatments, which might alter uterine flora.
• Most mares had anatomical or functional reproductive tract defects.
• Common predisposing events included:
• History of abortion or trauma around the time of parturition (8 out of 9 mares).
• Intrauterine chemical curettage (9 out of 10 mares), an invasive procedure likely affecting uterine health.
• Despite the condition, fertility outcomes were relatively positive, with 6 of 9 mares achieving pregnancies within 12 months post-diagnosis.
• Treatment was often prolonged, sometimes requiring surgical interventions such as uteropexy (suturing of the uterus to maintain its position).

Study 2: Prevalence and Microbial Analysis

• Analyzed 6,727 uterine samples collected in Ireland between 2019 and 2024.
• Samples included uterine swabs and uterine lavages, tested under different culture conditions.
• Key findings on fungal culture positivity:
• Uterine lavage samples had a 7% positivity rate for fungi.
• Swabs tested with specific fungal culture techniques yielded 19% positivity.
• Swabs tested without fungal culture techniques showed only 1% positivity.
• The choice of sampling method and culture protocol significantly influenced detection rates (statistically significant with p < 0.01).
• Prevalence of fungal endometritis increased significantly during the study period, with an odds ratio of 1.1, indicating a slight but notable annual rise.
• Fungal isolates from samples consisted roughly equally of yeasts (52.7%) and moulds (47.3%).

Diagnostic Accuracy of Cytology

• Evaluated 418 uterine lavages that were cytology tested and had negative bacterial cultures.
• Two cytological markers were assessed as predictors of fungal culture positivity:
• Polymorphonuclear neutrophils (PMNs), which are white blood cells indicative of inflammation.
• Fungal elements (FE), direct microscopic evidence of fungi.
• Cytology showed high specificity, meaning it rarely misclassified uninfected samples as positive:
• PMNs: specificity of 91.3% (CI 88.0% – 94.0%).
• Fungal elements: specificity of 99.7% (CI 98.5% – 100%).
• This suggests cytology is a useful adjunct diagnostic method, especially when bacterial cultures are negative but fungal infection is suspected.

Conclusions and Implications

• Both well-known and emerging risk factors for fungal endometritis in broodmares were identified, including prior antimicrobial use, reproductive tract defects, and invasive intrauterine procedures.
• The prevalence of fungal endometritis in broodmares in Ireland increased over the five-year study period, suggesting it is an emerging concern.
• Diagnostic methods impact detection rates considerably, with uterine lavage combined with specific fungal culture techniques yielding higher positivity rates.
• Cytological examination of uterine lavage fluid is highly specific and can assist in diagnosing fungal endometritis, particularly in cases with negative bacterial cultures.
• Effective management may require prolonged treatment and occasionally surgical intervention, but prognosis for fertility can remain acceptable.