Associations between the postpartum uterine and vaginal microbiota and the subsequent development of purulent vaginal discharge vary with dairy cow breed and parity

Insights into microbial compositions of the respiratory tract of neonatal dairy calves in a longitudinal probiotic trial through 16S rRNA sequencing

Introduction

Probiotics are a promising intervention for modulating the microbiome and the immune system, promoting health benefits in cattle. While studies have characterized the calf lung bacterial profile with and without oral probiotics, simultaneous probiotic effects on the bacterial populations of multiple sites along the respiratory tract have not been characterized.

Methods

This study utilized the same pre-weaning diary calf group from our previous studies to characterize the bacterial populations present in the nostril and tonsil across control and treatment groups and nine sampling time points. DNA was exacted from the nostril and tonsil swabs and lung lavage fluids, and 16S ribosomal RNA gene hypervariable regions 1-3 were subsequently sequenced.

Results

Temporal variation in alpha bacterial diversity within the nostril, tonsil, and lung samples was observed, indicating distinct bacterial compositions among sampling time points. Oral probiotic treatment did not change alpha diversity in any respiratory tissue, however, spatial variability in bacterial taxa composition was observed among the three respiratory tract regions. While the majority of differentially abundant taxa in probiotic treated calves were unique to their anatomical location, a few were common to two anatomical locations and one Finegoldia amplicon sequence variant was differentially abundant in all three anatomical locations.

Discussion

In conclusion, these findings contribute to the understanding of the dynamic nature of bacterial diversity and the potential effects of probiotics within the bovine respiratory tract and provides insight for future studies of probiotics on animal health, disease prevention, and management.

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.