Distribution and characteristics of extended spectrum β‑lactamase-producing Escherichia coli in stages of integrated broiler production in Korea
Bibliographic record
Abstract
Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli ( E. coli ) are a major public health concern owing to their multidrug resistance and potential for transmission through the food chain. The broiler industry is operated as a vertically integrated system; therefore, the ESBL-producing E. coli can easily disseminate across production stages. The objective of this study was to provide the distribution and characteristics of ESBL-producing E. coli in each production stage of three integrated broiler operations in Korea, from breeder hatcheries to commercial broiler farms. The prevalence of ESBL-producing E. coli isolates was significantly highest in commercial broiler hatcheries (36.8%–38.1%), followed by broiler breeder farms (15.4%–26.9%), commercial broiler farms (2.8%–18.2%), and breeder hatcheries (9.8%–12.8%) ( p < 0.05). Moreover, ESBL-producing E. coli isolates exhibited higher MIC 50 values ranging from 16 to >512 μg/mL against 3 rd - or 4 th -generation cephalosporins, higher multidrug resistance prevalence (94.6%–100%) and co-resistance to more antimicrobial classes than non-ESBL-producing E. coli isolates at all stages of broiler production. The most prevalent ESBL gene was bla CTX-M-55 (80.0%–100.0%) by production stages of integrated broiler operations ( p < 0.05), and class I integrons were detected in 25.5%-33.3% of isolates, but only 10 (6.2%) isolates harbored gene cassettes. Phylogenetic group B1 (59.4%–65.5%) was the most significantly prevalent, and combination of IncFIB and IncFII plasmids (46.4%–53.6%) were the most common replicon types across production stages ( p < 0.05). Moreover, a total of 136 (81.2%–90.0%) isolates showed transferability of ESBL genes, and most (91.9%–100.0%) of ESBL-producing E. coli isolates form biofilm. However, weak biofilm producers (54.5%–71.0%) were significantly prevalent than moderate or strong producers ( p < 0.05). These findings support that it is necessary to establish stringent strategies for the use of ceftiofur, 3 rd -generation cephalosporin, in broiler production in Korea, as demonstrated in Japan and Canada, where the prevalence of ESBL-producing E. coli decreased after the cessation of ceftiofur use in hatcheries.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| 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".