Characterization of Plasmid-Mediated <i>aphA</i> - <i>3</i> Kanamycin Resistance in <i>Campylobacter jejuni</i>
Bibliographic record
Abstract
A total of 254 isolates of Campylobacter jejuni and three isolates of Campylobacter coli, isolated from Sweden, Canada, and Egypt, were screened for kanamycin resistance. Eight strains of C. jejuni contained large plasmids that carried the aphA-3 kanamycin-resistance marker. In six plasmids, the aphA-3 gene was located downstream of an apparent insertion sequence, designated IS607*, which showed a considerable similarity to IS607, characterized on the chromosome of some Helicobacter pylori strains. In contrast, the other plasmids carried the aphA-3 gene as a part of a resistance cluster. This included three resistance markers encoding 6'-adenylyltransferase (aadE), streptothricin acetyltransferase (sat), and 3'-aminoglycoside phosphotransferase type III (aphA-3). The genetic organization of this resistance cluster suggests that it has been acquired by C. jejuni from a Gram-positive organism. The IS607* element was also observed in kanamycin-susceptible strains of C. jejuni on plasmids mediating tetracycline resistance. The kanamycin-resistance phenotype transferred along with tetracycline resistance by conjugation from four representative C. jejuni strains to a recipient strain of C. jejuni. The kanamycin-resistance determinant (aphA-3) was stably transferred from one of the four C. jejuni strains to a recipient strain of Escherichia coli. However, the C. jejuni plasmid, which also carries the tetO gene, was not maintained in E. coli. Pulsed-field gel electrophoresis revealed the integration of approximately 50 kb of the plasmid into the chromosome of the E. coli recipient.
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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 | 0.001 | 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) | 0.001 | 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".