Vaginal Microbiota Is Stable throughout the Estrous Cycle in Arabian Mares

Abstract

Lactic acid bacteria (LAB) dominate human vaginal microbiota and inhibit pathogen proliferation. In other mammals, LAB do not dominate vaginal microbiota, however shifts of dominant microorganisms occur during ovarian cycle. The study objectives were to characterize equine vaginal microbiota in mares by culture-dependent and independent methods and to describe its variation in estrus and diestrus. Vaginal swabs from 8 healthy adult Arabian mares were obtained in estrus and diestrus. For culture-dependent processing, bacteria were isolated on Columbia blood agar (BA) and Man Rogosa Sharpe (MRS) agar. LAB comprised only 2% of total bacterial isolates and were not related to ovarian phases. For culture-independent processing, V3/V4 variable regions of the 16S ribosomal RNA gene were amplified and sequenced using Illumina Miseq. The diversity and composition of the vaginal microbiota did not change during the estrous cycle. Core equine vaginal microbiome consisted of Firmicutes, Bacteroidetes, Proteobacteria and Actinobacteria at the phylum level. At the genus level it was defined by Porphyromonas, Campylobacter, Arcanobacterium, Corynebacterium, Streptococcus, Fusobacterium, uncultured Kiritimatiaellae and Akkermansia. Lactobacillus comprised only 0.18% of the taxonomic composition in estrus and 0.37% in diestrus. No differences in the relative abundance of the most abundant phylum or genera were observed between estrus and diestrus samples.

Characterization of oral and cloacal microbial communities of wild and rehabilitated loggerhead sea turtles (Caretta caretta)

“…Interestingly, a major proportion of reads in cloacal samples belonged to the novel Kiritimatiellaeota phylum (formerly in Verrucomicrobia) and were identified as uncultured eubacterium WCHB1-41 [68]. Uncultured WCHB1-41 have been found in equine vaginal and distal gut microbiome, and rumen of cattle [69][70][71]. Verrucomicrobia have been found in loggerhead cloacal and fecal samples [33,34] and it is possible that at least a portion of Verrucomicrobia reads would be classified as Kiritimatiellaeota if SILVA v.132 was used to assign the taxonomy, as in this study and study by Arizza et al [32].…”

A Review of the Diversity of the Genital Tract Microbiome and Implications for Fertility of Cattle

“…Typically, in cattle there is activation of the host defense system for removal the bacteria during endometrial involution within the first five weeks after calving [ 15 ]. It seems that the genital microbiome diversity is affected by many factors, some of, which are specific to the female such as estrous cyclicity [ 16 ] and pregnancy [ 17 ]. However, extrinsic factors such as nutrition [ 18 ] and genital pathologies [ 16 , 19 ] are equally important.…”

“…It seems that the genital microbiome diversity is affected by many factors, some of, which are specific to the female such as estrous cyclicity [ 16 ] and pregnancy [ 17 ]. However, extrinsic factors such as nutrition [ 18 ] and genital pathologies [ 16 , 19 ] are equally important. The majority of the genital tract bacteria are non-pathogenic and are present with the enterocytes in a symbiotic relationship.…”

The Semen Microbiome and Semen Parameters in Healthy Stallions

“…In recent years, the microbiome has proven to have a great impact on the systems they dwell on [ 5 , 6 , 7 , 8 , 9 ]. Unfortunately, the male reproductive tract has not received sufficient attention [ 10 , 11 ].…”