Pathological investigation and microbiological confirmation of Bartonella quintana endocarditis: A case of trench fever without the trench or fever
Bibliographic record
Abstract
Bartonella quintana is a louse-borne Gram-negative bacterium first discovered as the cause of trench fever during World War I. As B. quintana is not identified using routine culture with 5-day incubation, the pathogen is an agent of blood culture-negative endocarditis, particularly among individuals experiencing homelessness. Here, we describe a case of an 80-year-old man who presented in the winter of 2017 with severe aortic valve regurgitation resulting in exercise intolerance, requiring aortic valve replacement. Pathological assessment of the explanted aortic valve revealed changes of infective endocarditis. The presence of B. quintana in the valve tissue was confirmed using molecular methods including B. quintana -specific polymerase chain reaction (PCR) as well as PCR and sequencing of the 16S rRNA, heat shock protein ( hsp ), and RNA polymerase ( rpoB ) genes. The organism was subsequently grown from the patient’s blood. Serology revealed B. quintana IgG titres that were initially elevated at 1:4096, but decreased and were sustained at 1:1024, as the patient recovered following treatment with doxycycline and rifampin. Bartonella quintana endocarditis is recognized as a cause of culture-negative endocarditis, but the diagnosis can be difficult, as symptoms may be non-specific, and the organism requires special conditions (and media) for routine growth. This case emphasizes the value of pathological investigations and microbiology laboratory support in the setting of low clinical and intraoperative suspicion of infective endocarditis.
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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 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".