Genetic diversity among Canadian isolates of penicillin-resistant Streptococcus pneumoniae and characterization of penicillin-binding protein 1A, 2B and 2X mutations
Bibliographic record
Abstract
Increases in the prevalence of penicillin-nonsusceptible ' Streptococcus pneumoniae' can be attributed to the acquisition of altered penicillin-binding protein (PBP) genes and to the geographic spread of genetically related isolates with elevated B-lactam minimum inhibitory concentrations (MICs). The objective of this thesis was to characterize ' pbp1a, pbp2b' and 'pbp2x' mutations in Canadian isolates of penicillin-nonsusceptible 'S. pneumoniae' and to evaluate the relationship between genetic diversity and penicillin susceptibility as it pertains to the dissemination of resistance. Both pulsed-field gel electrophoresis (PFGE) and arbitrarily-primed PCR (AP-PCR) revealed homogeneity amongst penicillin-resistant isolates and exclusive heterogeneity amongst penicillin-intermediate and penicillin-susceptible isolates. Four penicillin-resistant isolates with homogenous typing profiles serotyped 19F, 23F and 14, indicating several instances of probable capsular serotype switching. Sequence analysis of the penicillin-binding domains of ' pbp1a, pbp2b' and 'pbp2x' revealed identical nucleotide and amino acid substitution patterns in all isolates with penicillin MICs >=1 [mu]g/ml. (Abstract shortened by UMI.)
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.003 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".