Unraveling the microbial diversity of bovine liver abscesses: isolation, identification, and genomic characterization of the <i>Bacteroides</i> found in hepatic lesions
Bibliographic record
Abstract
ABSTRACT Liver abscesses in cattle reduce animal performance, increase the environmental footprint of beef production, and cause significant economic losses. The low pH of the rumen resulting from the consumption of high grain diets damages the rumen epithelium and facilitates the translocation of opportunistic pathogens from the gastrointestinal tract into the bloodstream where they can colonize the liver, causing infection. Recently, 16s rRNA sequencing has revealed that 25%–50% of liver abscess microbiomes have prominent levels of Bacteroides . Due to the inability to reliably classify amplicon sequences beyond the genus level, the identity of these microbes remains unknown. We have employed a combination of culture-independent and culture-based methods to isolate and identify the Bacteroides associated with liver abscesses in cattle. Shotgun metagenomic sequencing and assembly of metagenome-assembled genomes generated four high-quality genomes, two of which were putatively identified as Bacteroides . These microbes were subsequently isolated from the purulent material of liver abscesses. Whole-genome sequencing conclusively identified these isolates as Bacteroides pyogenes and a previously unknown species of Bacteroides, revealing distinct differences from Bacteroides typically found in the gut. Carbohydrate utilization assays revealed that both organisms metabolize glycogen and glycosaminoglycans found in the extracellular matrix of the liver but display differences in substrate specificity. These data not only identify Bacteroides found in bovine liver abscesses but also provide new insights into the potential role that these organisms may play in this production-limiting disease. IMPORTANCE Liver abscesses (LAs) are commonly found in cattle raised in feedlots and result from a bacterial infection of the liver. Not only are LAs a concern for animal health, but they also impact growth efficiency, animal welfare, and cost the North American beef industry upwards of $120 million per annum. Recently, it has been found that 25%–50% of liver abscess microbiomes have prominent levels of Bacteroides ; however, to date, the biological relevance in LA pathogenesis and the identity of these bacteria are unknown. This research describes the isolation, identification, and genomic characterization of the Bacteroides found in bovine liver abscesses. These data provide a critical foundation for expanding our knowledge of the potential role Bacteroides play in liver abscess development and could contribute to the identification of novel targets for developing treatments to prevent this important production-limiting disease.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".