Uterine Microbiota of Dairy Cows With Clinical and Subclinical Endometritis

Abstract

The objective of this study was to characterize the uterine microbiota of dairy cows with clinical and subclinical endometritis and to identify the potential bacterial genera as well as their interactions associated with uterine disease. Uterine flush samples (n = 27) were collected from 13 healthy, 5 subclinical endometritic (SE), and 9 clinical endometritic (CE) cows at 30 days postpartum. Microbial DNA from uterine flush samples was subjected to sequencing of the 16S rRNA gene on the Illumina MiSeq platform. The uterine microbiota of healthy, SE, and CE cows had similarly complex microbial diversity, and shared 293 of 445 operational taxonomic units. However, endometritic and healthy cows could be discriminated by the relative abundance of bacterial genera. In CE cows, the uterine microbiota was characterized by increased abundance of Fusobacterium and unique presence of Trueperella and Peptoniphilus. For SE cows, known intrauterine pathogens were almost absent and the uterine microbiota was characterized by enrichment of Lactobacillus and Acinetobacter. Analysis of correlations between bacterial genera showed that the uterine microbiota exhibited two co-occurrence groups (i.e., the Lactococcus and the Fusobacterium COGs), indicating that the synergistic effect by co-occurred bacteria may be an important aspect of pathogenesis. Our findings support that common uterine pathogens are not associated with subclinical endometritis at 30 days postpartum and indicate the need of investigating the role of commensal bacteria such as Lactobacillus, and Acinetobacter in the inflammatory process of uterine endometrium.

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“…Santos et al [5] and Wang et al [21] reported that Proteobacteria was the most abundant phylum in the uterine microbiota of healthy cows; however, in this study, Proteobacteria was the second and third most abundant phylum in the samples obtained during summer and winter, respectively. The predominant taxa of Proteobacteria in the healthy uterine microbiota are also unclear; Santos et al [5] have indicated Pasteurella spp., and Bicalho et al [22] have demonstrated Escherichia spp.…”

“…Santos et al [5] and Wang et al [21] reported that Proteobacteria was the most abundant phylum in the uterine microbiota of healthy cows; however, in this study, Proteobacteria was the second and…”

“…In the uterine microbiota examined in this study, Firmicutes was the most abundant phylum, followed by Proteobacteria and Bacteroidetes. Machado et al [6] and Wang et al [21] also found that Firmicutes was the most abundant phylum, showing abundances of 52.3 and 76.7%, respectively, in the uterine microbiota of healthy cows at around one month postpartum. The predominant taxa of Firmicutes in the healthy uterine microbiota, however, is yet to be defined; Geobacillus spp.…”

“…(Bacillaceae, Machado et al [6]), Lactococcus spp. (Streptococcaceae, Wang et al [21]), and Ruminococcaceae [7] were reported as the most abundant components of healthy uterine microbiota.…”

“…At two months postpartum during summer, Moraxellaceae was found as the most abundant family in the uterine microbiota. Although members of Acinetobacter, a genus belonging to the family Moraxellaceae, have been reported to be associated with sub-clinical endometritis [21] and repeat breeder [23], Acinetobacter spp. can be found in diverse environments and their pathogenicity is regarded to be low.…”