Dynamics of uterine microbiota in postpartum dairy cows with clinical or subclinical endometritis

Abstract

our objectives were to describe and compare the uterine bacterial composition of postpartum Holstein cows diagnosed as healthy (n = 8), subclinical endometritis (SCE; n = 8), or clinical endometritis (CE; n = 5) in the fifth week postpartum. We did metagenomic analyses of 16S rRNA gene sequences from endometrial cytobrush samples at 10, 21, and 35 days in milk (DIM), and endometrial bacterial culture at 35 DIM. Uterine bacterial composition in healthy, SCE, and CE was stable at 10, 21, and 35 DIM. Alpha and beta diversities showed a different uterine microbiome from CE compared to healthy or SCE, but no differences were found between healthy and SCE cows. At the phylum level, the relative abundance of Bacteroidetes and Fusobacteria, and at genera level, of Trueperella was greater in ce than healthy or Sce cows. Trueperella pyogenes was the predominant bacteria cultured in cows with ce, and a wide variety of bacterial growth was found in healthy and Sce cows. Bacteria that grew in culture were represented within the most abundant bacterial genera based on metagenomic sequencing. the uterine microbiota was similar between Sce and healthy, but the microbiome in cows with ce had a loss of bacterial diversity. Multiple potential mechanisms that drive reproductive tract inflammatory disease in dairy cattle have been discovered 1,2 , but questions remain about the nature and causes of the different manifestations of reproductive tract infection and inflammation. Remarkable changes in the composition of the microbiome occur in postpartum cows that develop uterine disease 3,4 , but few papers have described the dynamics of the uterine microflora in healthy postpartum cows 5,6. A robust but well-regulated postpartum uterine inflammatory response is necessary to avoid disease 7. However, in early lactation, cows experience a state of immune dysfunction concurrent with changes in metabolism associated with physiologic adaptations to support milk production. Although certain phyla and genera of bacteria are reasonably consistently associated with some forms of uterine disease, the changes of the microbiome and the host interaction with it in the progression or avoidance of disease are only partially understood. Metritis (overt systemic illness due to uterine infection, characterized by fetid vaginal discharge) and purulent vaginal discharge (PVD) without systemic signs have commonly been associated with Trueperella pyogenes using culture-dependent methods 8,9,10. Clinical endometritis (CE) is PVD with concurrent endometritis based on > 5% polymorphonuclear (PMN) neutrophils 7,11. However, with the advent of cultureindependent methods using metagenomic sequencing, it has been shown that loss of diversity and increase in abundance of Bacteroides, Porphyromonas, and Fusobacterium were associated with metritis and PVD in postpartum cows 3,4,12. Numerous studies attempted to associate the presence of bacteria with subclinical endometritis (SCE; absence of PVD and > 5% endometrial PMN), but the role of pathogenic bacteria in SCE re...

Effects of parity, blood progesterone, and non-steroidal anti-inflammatory treatment on the dynamics of the uterine microbiota of healthy postpartum dairy cows

“…Although none of the cows in our study had clinical disease, there was variation in the proportions of endometrial PMN. Wang et al [ 5 ] and Pascottini et al [ 6 ] showed that neither the alpha and beta diversities nor the relative abundance of bacteria phyla and genera differed between healthy and SCE cows. However, it was shown that in cows with PVD (or clinical endometritis), there was an increased relative abundance of Trueperella in comparison to healthy or SCE [ 5 , 6 ].…”

“…For that study, 20 out of 42 Holstein cows received subcutaneous injections of meloxicam (0.5 mg/kg of body weight; Metacam, Boehringer Ingelheim Canada Ltd., Burlington, ON, Canada) once daily on 10, 11, 12 and 13 DIM (the rationale for this meloxicam dosing is described by Pascottini et al [ 14 ]. In a subsequent experiment using 21 cows from the underlying study, we compared the uterine bacterial composition of postpartum cows diagnosed with SCE (absence of mucopurulent vaginal discharge but with ˃ 5% endometrial polymorphonuclear neutrophils (PMN); n = 8), clinical endometritis (mucopurulent or purulent vaginal discharge with ˃ 5% endometrial PMN; n = 5), or healthy (neither SCE nor CE; n = 8) in the fifth week postpartum [ 6 ]. Uterine bacterial composition was not different between healthy and SCE cows, but uterine microbiota differed in cows with clinical endometritis [ 6 ].…”

“…In a subsequent experiment using 21 cows from the underlying study, we compared the uterine bacterial composition of postpartum cows diagnosed with SCE (absence of mucopurulent vaginal discharge but with ˃ 5% endometrial polymorphonuclear neutrophils (PMN); n = 8), clinical endometritis (mucopurulent or purulent vaginal discharge with ˃ 5% endometrial PMN; n = 5), or healthy (neither SCE nor CE; n = 8) in the fifth week postpartum [ 6 ]. Uterine bacterial composition was not different between healthy and SCE cows, but uterine microbiota differed in cows with clinical endometritis [ 6 ]. For the present study, the remaining 16 cows without clinical endometritis were classified as primiparous (n = 7) or multiparous (n = 9), treated with meloxicam (n = 7) or control (n = 9), and with high (˃ 1 ng/mL; n = 10) or low (≤ 1 ng/mL or absence of corpus luteum; n = 6) progesterone serum concentration at 35 DIM to compare their uterine bacterial composition.…”

“…The two former conditions are clearly associated with bacterial pathogens: metritis predominantly with Gram-negative anaerobes (e.g., Fusobacterium and Porphorymonas ) [ 4 ], and PVD with Trueperella pyogenes [ 5 ]. SCE has not been associated with changes in the uterine microbiota, in comparison to healthy cows [ 5 , 6 ]. The point at which uterine inflammation and uterine microbiota shifts from physiologic to pathologic and the determinants of these processes are only partially understood [ 7 ].…”

Enhanced Expression of miR‐34a Enhances Escherichia coli Lipopolysaccharide‐Mediated Endometritis by Targeting LGR4 to Activate the NF‐κB Pathway

“…Oxidative Medicine and Cellular Longevity confirmed the presence of fungal septicemia and Escherichia coli as the main pathogens responsible for endometritis in cattle, often isolated from the uterus [4,28,29]. LPS is an endotoxin found in the outer cell wall of Gram-negative bacteria [30,31]. To assess bacterial contamination in uterine tissue, Gram staining was conducted to examine the status and morphological feature of bacteria in the endometrium of uterine horn (n = 8) diagnosed with endometritis or pyometra.…”