Ewe Vaginal Microbiota: Associations With Pregnancy Outcome and Changes During Gestation

Antimicrobial susceptibility rates in gram-positive catalase-negative cocci from sheep and goat genital microbiota

Gram-positive catalase-negative cocci (GPCNCs) are significant components of the genital microbiota in sheep and goats. However, characterizing them can be difficult due to overlapping culture features and the limited information on their susceptibility to antibiotics. In this study, 97 foreskin and 13 vaginal swabs were investigated using a culturomic approach. Of 110 animals, 76 (69.09 %) hosted GPCNCs, including strains from Streptococcaceae (37, 33.64 %), Aerococcaceae (30, 27.27 %), Enterococcaceae (6, 5.45 %) and other minor species. With increasing antimicrobial resistance rates in livestock, surveillance programs are globally required, so we conducted a pilot study on GPCNCs isolated from the genital mucosa surfaces of sheep and goats using the minimal inhibitory concentration assay (MIC). Due to gaps in interpretative standard breakpoints, normalized resistance interpretation was used for setting epidemiological susceptibility cut-off values (COWTs). Of 57 suitable strains, the majority (80.71 %) showed high COWTs with decrease susceptibility to at least one antimicrobial class, with 22.81 % displaying multiresistant profiles. Of interest, combined resistances to beta-lactams, macrolides, lincosamides, and tetracyclines were detected in strains of Streptococcus plurianimalium. Further combinations, including resistance to beta-lactams, pleuromutilins, aminoglycosides, and lincosamides, were also recorded in both Streptococcus uberis and Enterococcus spp. strains. Being beta-lactams, macrolides, and tetracyclines the most used antibiotics in livestock worldwide, our results highlight the need for their prudent use. Collectively, our findings highlight that small ruminant genital microbiota can serve as reservoirs for opportunistic severe pathogens, often zoonotic, carrying multidrug resistances, thus standing for high risks for both animals and humans.

The effect of Phyllanthus emblica (Amla) fruit supplementation on the rumen microbiota and its correlation with rumen fermentation in dairy cows

Introduction

Medicinal plants, rich in phytochemicals like phenolic acids, flavonoids, and tannins, offer potential benefits in enhancing productivity, quality, and animal health. Amla fruit (Phyllanthus emblica) is one such plant with promising attributes. This study aimed to investigate the impact of fresh Amla fruit (FAF) supplementation on ruminal microbial composition and its correlation with rumen fermentation in lactating dairy cows.

Methods

The study employed a repeated crossover design involving eight ruminally cannulated mid-lactation Holstein dairy cows. Animals received varying levels of fresh Amla fruit supplementation (0, 200, 400, and 600 g/d).

Results

When 400 g/d of FAF was added to the diet, there was a significant increase in the relative abundance of Firmicutes (p = 0.02). However, at 200 g/d, the relative abundance of ruminal Bacteroidota was higher than the 0 and 400 g/d FAF supplementation (p < 0.01). LEfSe analysis identified distinct taxa, such as Clostridia vadinBB60 in the 200 g/d group, Oscillospiraceae in the 400 g/d group, and Elusimicrobium in the 600 g/d group. Notably, the random forest species abundance statistics identified Oscillospiraceae V9D2013 as a biomarker related to milk yield. Oscillospiraceae, Bacilli RF39, norank_f Prevotellaceae, and Bifidobacterium were positively correlated with ruminal total VFA and molar proportion of propionate, while Rikenellaceae RC9 gut group and Clostridia vadinBB60 were negatively correlated.

Discussion

FAF supplementation affects the abundance of beneficial microbes in a dose-dependent manner, which can improve milk yield, efficiency, rumen health, desirable fatty acids, and animal health.

In Vitro Interaction between Mycoplasma agalactiae and Small Ruminants' Endogenous Bacterial Strains of Enterococcus spp. and Coagulase-Negative Staphylococcus

Recently, an antimicrobial effect on Mycoplasma agalactiae (Ma), the main etiological agent of contagious agalactia (CA), was reported in vitro with strains of Enterococcus spp. from ovine and caprine milk. The aim of this work was to evaluate the interaction of Ma with the same Enterococcus spp. isolated from other anatomical locations (vagina) and other bacterial populations present in milk, such as coagulase-negative staphylococci (CNS). The vaginal Enterococcus strains and the raw milk CNS were isolated from sheep and goats. Experimental in vitro conditions were prepared to assess the growth of Ma with and without the presence of these strains. The selected vaginal strains were identified as Enterococcus (E.) hirae and E. mundtii, and the strains of CNS were identified as Staphylococcus petrasii. Different interactions of Ma with ovine and caprine wild vaginal strains of Enterococcus and dairy strains of CNS are described for the first time: Ma can grow exponentially during 15 h with the selected strains, although with certain strains, its optimal growth can be negatively affected (p < 0.05). The colonization and/or excretion of Ma could, therefore, be influenced by certain endogenous bacterial strains. Our results increase the knowledge about possible bacterial ecology dynamics surrounding CA.

Temporal changes in ewe vaginal microbiota throughout gestation

Introduction

Numerous factors are known to influence reproductive efficiency in ewes, but few studies have investigated the potential role of vaginal microbiota in sheep reproductive success. The objective of this study was to thoroughly characterize the ewe vaginal microbiota throughout the course of pregnancy.

Methods

Vaginal samples were collected from 31 pregnant Hampshire and Hampshire X Suffolk crossbred ewes on a weekly basis from pre-breeding to pregnancy testing and then biweekly until just after lambing. To characterize the vaginal microbial communities, DNA was extracted and 16S rRNA gene Illumina MiSeq amplicon sequencing was performed.

Results and Discussion

Alpha diversity metrics indicated an increase in species richness, evenness, and overall diversity throughout gestation. Distinct shifts in the bacterial communities were observed during gestation and were segregated into three periods: early gestation, a transitional period and mid/late gestation. During early gestation, Actinobacillus, Histophilus, and unclassified Leptotrichiaceae were found in greater relative abundance. During the transitional period, a population shift occurred characterized by increasing relative abundance of Streptococcus and Staphylococcus. During mid/late gestation, Staphylococcus, Streptococcus, and Ureaplasma had the greatest relative abundance. These shifts in the microbial population throughout the ewe's gestation are likely related to hormonal changes triggered by the growing conceptus, specifically increasing blood concentration of progesterone. The transitional period shift in vaginal microbial communities potentially aligns with the placental take-over of progesterone production from the corpus luteum at approximately day 50 after conception (gestational week 7). Understanding the observed variability of the vaginal microbiota throughout pregnancy will allow for future comparison of ewes that did not become pregnant or had abnormal pregnancies, which could lead to the discovery of potential bacterial biomarkers for pregnancy outcome; this understanding could also lead to development of probiotics to improve sheep reproductive success.

Fecal and vaginal microbiota of vaccinated and non-vaccinated pregnant elk challenged with Brucella abortus

Introduction

Brucella abortus is the causative agent of brucellosis in cattle and in humans, resulting in economic losses in the agricultural sector and representing a major threat to public health. Elk populations in the American Northwest are reservoirs for this bacterium and transmit the agent to domestic cattle herds. One potential strategy to mitigate the transmission of brucellosis by elk is vaccination of elk populations against B. abortus; however, elk appear to be immunologically distinct from cattle in their responses to current vaccination strategies. The differences in host response to B. abortus between cattle and elk could be attributed to differences between the cattle and elk innate and adaptive immune responses. Because species-specific interactions between the host microbiome and the immune system are also known to affect immunity, we sought to investigate interactions between the elk microbiome and B. abortus infection and vaccination.

Methods

We analyzed the fecal and vaginal microbial communities of B. abortus-vaccinated and unvaccinated elk which were challenged with B. abortus during the periparturient period.

Results

We observed that the elk fecal and vaginal microbiota are similar to those of other ruminants, and these microbial communities were affected both by time of sampling and by vaccination status. Notably, we observed that taxa representing ruminant reproductive tract pathogens tended to increase in abundance in the elk vaginal microbiome following parturition. Furthermore, many of these taxa differed significantly in abundance depending on vaccination status, indicating that vaccination against B. abortus affects the elk vaginal microbiota with potential implications for animal reproductive health.

Discussion

This study is the first to analyze the vaginal microbiota of any species of the genus Cervus and is also the first to assess the effects of B. abortus vaccination and challenge on the vaginal microbiome.

Description of the vaginal microbiota in nulliparous ewes during natural mating and pregnancy: preliminary signs of the male preputial microbiota modulation

The vaginal microbiota plays a key role in animals' health. Understanding its diversity and composition and associated changes occurring through the reproductive cycle represents valuable knowledge to disclose the mechanisms leading to dysbiosis and eventually to infection. Even if the human vaginal microbiota has been thoroughly studied, scarce research has been conducted on the vaginal microbiota of livestock. In this study, 16S rRNA gene-based sequencing was performed on vaginal samples of ten nulliparous ewes at three different sampling points: before the estrus synchronization protocol (T0), at the time of estrus before mating (Testrus), and the day of the pregnancy diagnosis (Tpreg). Preputial samples from the three males collected pre and post-mating were also analyzed. Firmicutes, Proteobacteria, Bacteroidetes, and Actinobacteria were the most abundant phyla in vaginal samples. The most abundant genera were Porphyromonas, Anaerococcus, and Peptinophilius. Vaginal microbiota biodiversity decreased during pregnancy. Tenericutes (Ureaplasma spp.) increased significantly at Tpreg in both pregnant and non-pregnant ewes. Differences were observed between pregnant and non-pregnant ewes at Tpreg where pregnant ewes had a significantly higher abundance of Actinobacillus spp. and Ureaplasma spp. Ewes that were diagnosed with pregnancy at Tpreg showed a decreased abundance of gram-negative bacteria such as Bacteroidales, Campylobacterales, and Enterobacteriales. In addition, a significant decrease in the relative abundances of genera within Firmicutes, such as Alloicoccus (Lactobacillales), Atopostipes (Lactobacillales), and an uncultured bacteria W5053 from Family XI (Firmicutes, Clostridiales) was observed in non-pregnant ewes at Tpreg. The four most abundant phyla in the rams' prepuce were the same as in the ewes' vagina. The most abundant genus was Corynebacterium. No major differences were observed in the ram's preputial microbiota between pre and post-mating samples. Nevertheless, the differences in the taxonomic composition of ewes' vaginal microbiota between Testrus and Tpreg could be explained by the exposure to the preputial microbiota. This study offers new insights into the effects of several key steps of the ewe's reproductive cycle such as estrus-synchronization protocol, mating, and pregnancy on ovine vaginal microbiota. The knowledge of the microbiota dynamics during the reproductive cycle can help improve the reproductive outcomes of dams by identifying biomarkers and putative probiotics.

Blood Metabolites and Faecal Microbial Communities in Nonpregnant and Early Gestation Ewes in Highly Cold Areas

Ewes undergo complex metabolic changes during pregnancy. Understanding the specific process of these changes is a necessary prerequisite in ewes for regulating and intervening in order to maintain pregnancies. However, there have been relatively few studies on the specific changes that occur in nutritional metabolism in pregnant ewes during early gestation, especially for some landrace ewes in highly cold areas. Therefore, this study aimed to (1) elucidate the changes in metabolites and microbial communities in pregnant ewes during early gestation using metabolomics and 16S ribosomal RNA gene (rDNA) amplicon sequencing approaches, and to (2) discover novel early pregnancy-induced biomarkers in the blood and faeces. Rams were placed together with ewes on D0 and removed on D45. During early gestation, blood and faecal samples were collected from ewes in a highly cold area for analysing the metabolites and microbial communities; these were retrospectively classified as the early gestation pregnant (EP) ewe group or the nonpregnant (NP) ewe group based on the lambing status recorded during the expected delivery period. The differences in the plasma biochemical parameters, plasma metabolites, and faecal microbial communities of pregnant and nonpregnant ewes were characterised. The GC, IL-6, O-acetyl-l-serine, L-glutamine, and 6-acetamido-2-oxohexanoic acid were screened out as potential biomarkers for evaluating the occurrence of early pregnancy. These novel early pregnancy-induced metabolites discovered in ewes might allow for the development of technologies to detect early pregnancies in sheep in highly cold areas.

Exploring the microbiome of two uterine sites in cows

Bacterial communities in the mammalian reproductive system can be rich and diverse, differing in structure and quantity depending on location. In addition, its microbiome is associated with the state of health of this tract and reproductive success. This study evaluated the microbiome composition of the uterine body (UB) and uterine horn mucosa (UH) samples using 16S rRNA sequencing of samples extracted from cows in the Amazon region. It was observed that four main phyla were shared between the uterine sites: Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria. Linear discriminant analysis effect size and heat tree analysis showed that members of Lachnospiraceae (NK3A20 group) and Oscillospiraceae were significantly more abundant in the UB than in UH. In addition, there are more unique genera in the UB than in the UH. A higher bacterial load in UB than in UH is expected because of the exposure to external factors of UB. However, comparing the site's communities through beta diversity did not generate well-defined clustering. Thus, it can be attributed to the closeness of the sites, which would make the niches similar ecologically and microbiologically. Therefore, this research provides knowledge to understand biomarkers in the prior reproduction period.

Comparative Analysis of the Pre-Parturition and Post-Parturition Genital Tract Microbiota in Plateau Bangor Sewa Sheep

(1) Background: Bangor Sewa sheep are an economically significant livestock species on the plateau. The roles of microbiota in reproduction are complex and critical for animal health. But little is known currently about the microbiome of plateau Bangor Sewa sheep. The purpose of this study was to discover the changes in the genital tract microbiota of pre- and post-partum Bangor Sewa sheep. (2) Methods: Samples from the birth canal were obtained for 16S rRNA sequencing, three days before and after delivery, respectively. (3) Results: The results showed that there was a noticeable difference in three phyla and 74 genera between the pre- and post-parturition groups in the microbiota of Bangor Sewa sheep. The changes included a decrease in the abundance of genera related to health (unclassified_Cellulomonadaceae, Cellulomonas, Fibrobacti, Flavobacterium, Eubacterium_ventriosum_group, Acetitomaculum, Aeromicrobium, Dietzia, Romboutsia, Ruminococcus, etc.) and an increased abundance of negatively related genera (Nocardioides, unclassified_Clostridia, Sphingobacteriaceae, unclassified_Ruminococcaceae, Prevotellaceae_UCG_004, Micromonospora, Streptococcus, Facklamia, Bosea, etc.) spp. (4) Conclusions: Microbes can serve as indicators of the physical state of Bangor Sewa sheep. These findings laid the foundation for deciphering the effects of microbial changes during birth on the reproductive health of plateau Bangor Sewa sheep.

Reproductive Microbiomes in Domestic Livestock: Insights Utilizing 16S rRNA Gene Amplicon Community Sequencing

Advancements in 16S rRNA gene amplicon community sequencing have vastly expanded our understanding of the reproductive microbiome and its role in fertility. In humans, Lactobacillus is the overwhelmingly dominant bacteria within reproductive tissues and is known to be commensal and an indicator of fertility in women and men. It is also known that Lactobacillus is not as largely abundant in the reproductive tissues of domestic livestock species. Thus, the objective of this review is to summarize the research to date on both female and male reproductive microbiomes in domestic livestock species (i.e., dairy cattle, beef cattle, swine, small ruminants, and horses). Having a comprehensive understanding of reproductive microbiota and its role in modulating physiological functions will aid in the development of management and therapeutic strategies to improve reproductive efficiency.

A Distribution-Free Model for Longitudinal Metagenomic Count Data

Longitudinal metagenomics has been widely studied in the recent decade to provide valuable insight for understanding microbial dynamics. The correlation within each subject can be observed across repeated measurements. However, previous methods that assume independent correlation may suffer from incorrect inferences. In addition, methods that do account for intra-sample correlation may not be applicable for count data. We proposed a distribution-free approach, namely CorrZIDF, which extends the current method to model correlated zero-inflated metagenomic count data, offering a powerful and accurate solution for detecting significance features. This method can handle different working correlation structures without specifying each margin distribution of the count data. Through simulation studies, we have shown the robustness of CorrZIDF when selecting a working correlation structure for repeated measures studies to enhance the efficiency of estimation. We also compared four methods using two real datasets, and the new proposed method identified more unique features that were reported previously on the relevant research.