Effect of β-lactam antibiotic resistance gene expression on the radio-resistance profile of E. coli O157:H7
Bibliographic record
Abstract
Some pathogens might develop favorable global adaptation in response to certain stress treatments resulting in enhanced virulence and/or resistance to a different stress. β-lactam resistance, as well as ampC and ampG genes involved in this resistance, were studied to evaluate their possible role in Escherichia coli O157:H7 (E. coli) radioresistance. E. coli adapted to 25, 15 or 7 μg/mL of kanamycin or carbenicillin, were produced and treated with sensitization (0.4 kGy) or lethal (1.5 kGy) irradiation doses. In E. coli O157:H7, irradiation treatment at 0.4 kGy dose increased ampC and ampG expression respectively by 1.6 and 2-fold in the wild type strain (Wt) but up to by 2.4 and 3.4-fold when the strain was beforehand adapted to 25 μg/mL of carbenicillin (Carb25). Accordingly, ΔampC and ΔampG mutants and E. coli adapted to 25 μg/mL of kanamycin were more sensitive to 0.4 kGy treatment than Wt. While, E. coli Carb25 or overexpression of ampC and ampG provided complete resistance to 0.4 kGy and were even able to survive and grow after exposure to a normally lethal 1.5 kGy irradiation dose. We further noticed that these strains can tolerate other stresses like oxidative, cold and heat shocks. This demonstrates that carbenicillin adaptation promotes resistance to γ-irradiation and to other stresses, likely at least through increased AmpC and AmpG expression. These results are important for the food industry and particularly when considering the use of irradiation for food preservation of meat obtained directly from animals fed β-lactam antibiotics.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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 teacher head, 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".