Panton-Valentine leukocidin in pediatric community-acquired Staphylococcus aureus infections
Bibliographic record
Abstract
PURPOSE: Panton-Valentine Leukocidin (PVL) is an exotoxin produced by strains of Staphylococcus aureus (SA). Its importance as a virulence factor is controversial. We aim to further characterize the role of PVL in pediatric community-acquired SA infections. METHODS: In a cohort study conducted from July to November 2006, we prospectively collected all strains of SA isolated at the Montreal Children's Hospital causing community-acquired infections in children aged 18 years or younger. The strains were analyzed for the presence of the PVL encoding genes by PCR and were phage typed. Strains resistant to methicillin or pvl+ were analyzed by pulsed-field gel electrophoresis. A medical chart review blinded to patient pvl status was performed to retrieve demographic and clinical data. Data were analyzed by logistic regression. RESULTS: We identified 74 pediatric community-acquired SA infections. Nineteen strains (25.7%) were positive for the pvl genes. Four isolates (5.4%) were resistant to methicillin and three of these were pvl+. No predominant clone was identified by phage typing or pulsed field gel electrophoresis. Pvl+ and pvl- infections were statistically similar for patient age, hospital admission, length of hospital stay, invasive disease, intravenous antibiotics and outcomes. Pvl+ strains were more likely to cause abscesses (OR 20.79; 95% CI 4.93 - 87.58), less likely to cause superficial skin infections (OR 0.18; 95% CI 0.05 - 0.64) and less likely to be resistant to erythromycin (OR 0.048; 95% CI 0.004 - 0.52). CONCLUSIONS: In a clonally heterogeneous population of pediatric community-acquired SA infections, pvl+ strains were associated with abscess formation and erythromycin susceptibility, but not invasive disease.
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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 | 0.001 | 0.007 |
| 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 | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".