Comparison of uterine microbiome between healthy and chronic endometritis mares

This paper leads to so many questions. Why does this occur? Is the change in microbiome a cause or effect of chronic endometritis? What is the best way to try and establish a more normal microbiome, and does such action lead to better long term reproductive outcomes? Some of the answers may give us a new way to measure uterine health and help measure the effectiveness of some of our current treatments.
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Metagenomic analysis unravels novel taxonomic differences in the uterine microbiome between healthy mares and mares with endometritis
Vet Med Sci. 2024 Mar;10(2):e1369. doi: 10.1002/vms3.1369.
Authors
Aeknath Virendra 1 , Sarita U Gulavane 1 , Zulfikar A Ahmed 2 , Ravi Reddy 3 , Ravindra J Chaudhari 1 , Sandeep M Gaikwad 1 , Raju R Shelar 1 , Shailesh D Ingole 4 , Varsha D Thorat 5 , Afroza Khanam 6 , Firdous A Khan 6
Affiliations

1 Department of Animal Reproduction, Gynecology and Obstetrics, Mumbai Veterinary College, Mumbai, Maharashtra, India.
2 Equus Stud Farm, Pune, Maharashtra, India.
3 Nanoli Stud and Agricultural Farm, Pune, Maharashtra, India.
4 Department of Veterinary Physiology, Mumbai Veterinary College, Mumbai, Maharashtra, India.
5 Department of Veterinary Microbiology, Mumbai Veterinary College, Mumbai, Maharashtra, India.
6 Department of Large Animal Medicine and Surgery, School of Veterinary Medicine, St. George’s University, Grenada, West Indies.

PMID: 38357732
PMCID: PMC10867593
DOI: 10.1002/vms3.1369

Free PMC article
Abstract

Background: The application of high throughput technologies has enabled unravelling of unique differences between healthy mares and mares with endometritis at transcriptomic and proteomic levels. However, differences in the uterine microbiome are yet to be investigated.

Objectives: The present study was aimed at evaluating the differences in uterine microbiome between healthy mares and mares with endometritis.

Methods: Low-volume lavage (LVL) samples were collected from the uterus of 30 mares classified into healthy (n = 15) and endometritis (n = 15) based on their reproductive history, intrauterine fluid accumulation, gross appearance of LVL samples, endometrial cytology and bacterial culture. The samples were subjected to 16S rRNA sequencing.

Results: Notable differences in the uterine microbiome were observed between healthy mares and mares with endometritis at various taxonomic levels. In healthy mares, the most abundant phylum, class, order and family were Firmicutes, Bacilli, Bacillales and Paenibacillaceae, respectively. In contrast, the most abundant corresponding taxonomic levels in mares with endometritis were Proteobacteria, Gammaproteobacteria, Enterobacterales and Enterobacteriaceae, respectively. At the genus level, Brevibacillus and Paenibacillus were more abundant in healthy mares, whereas Escherichia, Salmonella and Klebsiella were more abundant in mares with endometritis. In healthy mares, Brevibacillus brevis was the most abundant species, followed by Brevibacillus choshinensis and Paenibacillus sp JDR-2. However, in mares with endometritis, Escherichia coli was the most abundant species, followed by Salmonella enterica and Klebsiella pneumoniae.

Conclusions: These results confirmed the previously reported presence of a uterine microbiome in healthy mares and helped unravel some alterations that occur in mares with endometritis. The findings can potentially help formulate new approaches to prevent or treat equine endometritis.

Keywords: bacteria; equine; inflammation; metagenomics; uterus.

© 2024 The Authors. Veterinary Medicine and Science published by John Wiley & Sons Ltd.
Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as potential conflicts of interest.