Endometrial and vaginal microbiome in donkeys with and without clinical endometritis

Abstract

Endometrial and vaginal microbiomes are critical in the study of endometritis, which is an important cause of infertility in donkeys. Our objective was to investigate the difference of the endometrial and vaginal microbiomes between healthy donkey jennies (group C) and jennies with endometritis (group E). Endometrial and vaginal swab samples were collected, and the 16 s rRNA gene amplicon high-throughput sequencing technique was applied to identify the microbial composition in the samples. A similar microbial composition pattern was found between endometrial and vaginal samples, which indicated the impact of the vaginal microbiome on the endometrial microbial environment and health. There was a significant difference of endometrial and vaginal swab samples between the two groups. Ruminococcaceae and Lachnospiraceae were significantly more abundant in endometrial and vaginal microbiomes of group E than in group C. Their dominance was consistent with increased anaerobic bacterial taxa in the functional analysis, which might be associated with the pathogenesis of endometritis in donkeys. Sphingomonadaceae, a bacterial family reported in bovine semen, was statistically more abundant in endometrial microbiome of group E than in group C, which might suggest an association between high abundance of Sphingomonadaceae possibly due to uncleared semen and donkey endometritis. Our study revealed the composition of the vaginal and endometrial microbiomes in healthy and endometritis donkeys. These findings will provide more insights into the pathogenesis of donkey endometritis.

Clinical Aspects of Bacterial Distribution and Antibiotic Resistance in the Reproductive System of Equids

“…zooepidemicus isolates from individuals with reproductive disorders were found to carry a higher number of virulence factors genes than isolates from clinically healthy jennies [ 31 , 32 , 33 ]. Recent studies have revealed that the microbiome of the vagina of healthy jennies included mostly the phyla Proteobacteria (most abundant family: Moraxellaceae), Firmicutes (most abundant family: Lactobacillaceae), Bacteroidetes (most abundant family: Sphingobacteriaceae) and Actinobacteria (most abundant family: Corynebacteriaceae) [ 34 ].…”

“…In sharp contrast to relevant results in mares, investigation of uterine infections of donkeys has been limited [ 33 , 34 , 63 ]. The uterine microbiome of healthy jennies was found to be composed mainly of the phyla Proteobacteria (most abundant family: Moraxellaceae), Firmicutes (most abundant family: Lactobacillaceae) and Actinobacteria (most abundant family: Corynebacteriaceae) [ 34 ].…”

“…In sharp contrast to relevant results in mares, investigation of uterine infections of donkeys has been limited [ 33 , 34 , 63 ]. The uterine microbiome of healthy jennies was found to be composed mainly of the phyla Proteobacteria (most abundant family: Moraxellaceae), Firmicutes (most abundant family: Lactobacillaceae) and Actinobacteria (most abundant family: Corynebacteriaceae) [ 34 ]. However, in cases of endometritis, changes were evident in the frequency of abundance at family level, with Enterobacteriaceae, Lactobacillaceae and Sphingomonadaceae being the predominant families [ 34 ].…”

“…The uterine microbiome of healthy jennies was found to be composed mainly of the phyla Proteobacteria (most abundant family: Moraxellaceae), Firmicutes (most abundant family: Lactobacillaceae) and Actinobacteria (most abundant family: Corynebacteriaceae) [ 34 ]. However, in cases of endometritis, changes were evident in the frequency of abundance at family level, with Enterobacteriaceae, Lactobacillaceae and Sphingomonadaceae being the predominant families [ 34 ]. The abundance of the Sphingomonadaceae family has been postulated to be a consequence of using contaminated semen [ 34 ].…”

“…However, in cases of endometritis, changes were evident in the frequency of abundance at family level, with Enterobacteriaceae, Lactobacillaceae and Sphingomonadaceae being the predominant families [ 34 ]. The abundance of the Sphingomonadaceae family has been postulated to be a consequence of using contaminated semen [ 34 ].…”