CTX-M-Producing Escherichia coli: History, Molecular Epidemiology and Laboratory Detection
Bibliographic record
Abstract
Gisele Peirano,1,2 Andrea Endimiani,3 Johann DD Pitout1,2,4 1Division of Microbiology, Alberta Precision Laboratories, Calgary, Alberta, Canada; 2Department of Pathology and Laboratory Medicine, Cummings School of Medicine, University of Calgary, Calgary, Alberta, Canada; 3Institute for Infectious Diseases, University of Bern, Bern, Switzerland; 4Department of Medical Microbiology, University of Pretoria, Pretoria, Gauteng, South AfricaCorrespondence: Johann DD Pitout, Email jpitout@ucalgary.caAbstract: From being a curiosity in the 1990s, CTX-M-producing Escherichia coli invaded most parts of the globe during the 2000s and 2010s, with multidrug-resistant (MDR) clone ST131 and CTX-M-15 leading the charge. The most widely distributed CTX-M types, with the highest global frequencies (up to 70% in certain lower- and middle-income countries), are CTX-M-15, CTX-M-14 and CTX-M-27. E. coli isolates with blaCTX-M-27 are currently emerging globally. The worldwide ascendancy of E. coli with blaCTX-M genes occurred via the spread of IncF plasmids between isolates and the existence of certain successful clones (eg, ST131) that acted as repositories for these genes. This is an impressive “gene survival strategy” that aided with the endurance of blaCTX-M in different environments, including the community and hospitals. The detection of extended-spectrum β-lactamase (ESBL)-producing E. coli (including CTX-M isolates) in clinical laboratories is reasonably straightforward. However, different methodologies (eg, immunogenic and genomic) have recently become available to specifically identify CTX-Ms in bacterial isolates as well as human specimens. The role of such tests is currently unclear. E. coli with CTX-M β-lactamases have indirectly been driving the carbapenemase pandemic and are forces to be reckoned with.Keywords: Escherichia coli, CTX-M β-lactamases, MDR high-risk clones, ST131
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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 | 0.004 | 0.009 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.006 | 0.004 |
| Science and technology studies | 0.000 | 0.002 |
| Scholarly communication | 0.002 | 0.003 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.001 | 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".