Detection of carbapenemase activity in Enterobacteriaceae: comparison of the carbapenem inactivation method versus the Carba NP test: Table 1.
Bibliographic record
Abstract
Sir, Carbapenem resistance mediated by plasmid-encoded carbapenemases has emerged worldwide and become a major concern.1 The detection of the activity of carbapenemases has a strong impact on hospital infection control, because the detection of their presence can initiate measures to avoid potential outbreaks and lateral spread of the resistance. Although molecular detection by PCR is considered the gold standard for carbapenemase gene identification, some limitations are clearly recognized. Between them, false-negative results (the presence of a carbapenemase gene not tested in the PCR reaction, or mutations affecting annealing of primers) or the detection of inactive genes (i.e. no carbapenemase expression) can delay infection-control measures or, oppositely, initiate them when they are not required. A fast and accurate phenotypic method, the Carba NP test (CNPt), was developed; it detects carbapenemase activity with very high sensitivity and specificity and lower costs compared with those of PCR.2 This method is now being recommended in the CLSI guidelines for carbapenemase activity detection.3 However, recent studies have shown that this test has lower sensitivity particularly against isolates expressing β-lactamases with low carbapenemase activity, such as OXA-48-like, or expressing mucoid colonies.4,5 Another new test, the carbapenem inactivation method (CIM), has shown very promising results based on its sensitivity, specificity, low cost and easy interpretation.6 Briefly, the CIM consists of two steps: (i) incubation of a meropenem disc with the isolate to be tested; and (ii) incubation of this meropenem disc with the Escherichia coli ATCC strain. After this second incubation step, the presence of carbapenemase activity can be easily detected: the absence of an inhibition zone indicates enzymatic hydrolysis of meropenem during the first incubation step, whereas a ‘clear inhibition zone’ appears when the tested isolate does not express carbapenemase activity.6 The goal of this study was to compare the performance of the CIM and the CNPt against a panel of well-characterized enterobacteria.
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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 | 0.006 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.003 | 0.002 |
| Insufficient payload (model declined to judge) | 0.005 | 0.003 |
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".