Identification and distribution of Brachyspira species in feces from finishing pigs in Argentina

Multi-omics analyses of serum metabolome, urine metabolome and gut microbiome reveal dysregulated glycerophospholipid metabolism in subacute cadmium-exposed wistar rats

Data is limited on intestinal microbiota and metabolites in healthy residents exposed to cadmium (Cd), a population uniquely susceptible to Cd toxicity through contaminated foods. In this study, the 16S rRNA gene sequencing, serum metabolomics and urine metabolomics were performed to examine the alterations of gut microbiota and metabolomics profile of wistar rats exposed to Cd. These findings indicated that Cd exposure markedly altered the structure of gut microbial community, reduced significantly microbiome diversity, and identified 5 phyla and 6 genera with significant changes. Specifically, the levels of Pseudoxanthomonas and Anaerovibrio upregulated and that of Akkermansia, Brachyspira, Aggregatibacter and SMB53 reduced in rats treated with Cd. Metabolomics profiles of the urine and serum of Cd-treated rats revealed that the abundance of glycerophospholipid metabolites and their derivatives were markedly altered. Glycerophospholipid metabolic pathways that were markedly enriched in metabolomics in both samples was also significantly predicted in gut microbiota analysis. Further, interaction analysis predicted that there might be a relationship between the differential glycerophospholipid metabolites and affected bacteria genera induced by Cd. These results suggested that subacute Cd could disrupt the intestinal microecologica equilibrium and glycerophospholipid metabolic homeostasis, and also provided potential differential microbiota and glycerophospholipid biomarkers between subacute Cd-exposed rats and healthy rats.

Carriage of Brachyspira hyodysenteriae on common insect vectors

The interactions of likely insect and murine vectors of the causative agent of swine dysentery, Brachyspira hyodysenteriae, were investigated. Insects were collected and analysed from 3 pig farms positive for B hyodysenteriae. Within these farms, several Musca domestica and Orphyra adult fly, Blatta sp. cockroach digestive tracts and hover fly (Eristalis sp) pupal form contents were positive in a standard PCR assay for B hyodysenteriae, whereas all other insect samples on these and case control farms were negative. In challenge exposure studies, B hyodysenteriae DNA was detected in the digestive tract of cockroaches and M domestica flies from day 1 post-inoculation with cultured B hyodysenteriae, for up to 5 days or 10 days respectively, while control non-inoculated insects remained negative. Isolates consistent with B hyodysenteriae were only cultured from frass samples of these inoculated cockroach and flies on days 1-3 post-inoculation. Isolates consistent with B hyodysenteriae were detected by analysis of agar plates exposed to live B hyodysenteriae-inoculated adult flies wandering and feeding on these plates for 20 min per day. In generational challenge inoculation studies, B hyodysenteriae was detected in the adult emergent flies, and internal components of fly pupae on days 1-7 of the pupation period, after being inoculated with B hyodysenteriae as larvae. Five-week-old conventional mice (C3H) that consumed 2 meals of B hyodysenteriae-infected flies remained negative for B hyodysenteriae throughout the next 10 days. The results indicated that pathogenic Brachyspira sp have a limited ability to internally colonise likely insect vectors and do not readily transmit infection to mice. However, the insect vectors analysed were demonstrably capable of mechanical carriage and likely on-farm involvement in consequence.