Class 3 integrons : machanistical and epidemiological aspects
Bibliographic record
Abstract
Integrons are bacterial genetic elements able to capture and express genes embedded within gene cassettes. They are widely described among Gram-negative bacteria and generally confer a multidrug resistance phenotype. Resistance integrons (RI) play an important role in the acquisition of antibiotic resistance. There are 3 main classes of RI. Class 3 RI has been poorly studied class with less than ten fully IR3 characterized. Objectives of this thesis were (i) to conduct an epidemiological study of class 3 RI in France and Cameroon and (ii) to better understand the modes of expression of the integrase and cassettes of IR3. We described 3 new class 3 RI isolated from environmental bacteria belonging to genus Aeromonas, Acinetobacter and Citrobacter. Gene cassettes encoded resistance to betalactams, aminoglycosides and quaternary ammonium compounds. We also described IR3 from three Delftia strains (2 D.acidovorans and 1 D.tsuruhatensis) in Africa containing cassettes that do not encode antibiotic resistance. The fundamental part of the work showed that the PintI3(1) promoter is involved in the expression of the intI3 gene. Furthermore, we demonstrated that variants of the Pc promoter and variants of the PintI3(1) promoter are functional with different strengths. These results showed that the environment may constitute a reservoir of class 3 integrons and that these genetic elements could play an important role in the spread of the resistance in this ecosystem.
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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 | 0.005 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.003 | 0.002 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.018 | 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".