Canadian Multicenter Laboratory Study for Standardized Second-Line Antimicrobial Susceptibility Testing of Mycobacterium tuberculosis
Bibliographic record
Abstract
The purpose of this study was to establish a standardized protocol for second-line antimicrobial suscepti-bility testing of Mycobacterium tuberculosis using the Bactec MGIT 960 system in Canadian laboratories. Four Canadian public health laboratories compared the susceptibility testing results of 9 second-line antimicrobials between the Bactec 460 and Bactec MGIT 960 systems. Based on the data generated, we have established that the Bactec MGIT 960 system provides results comparable to those obtained with the previous Bactec 460 method. The critical concentrations established for the testing of the antimicrobials used are as follows: amikacin, 1 g/ml; capreomycin, 2.5 g/ml; ethionamide, 5 g/ml; kanamycin, 2.5 g/ml; linezolid, 1 g/ml; moxifloxacin, 0.25 g/ml; ofloxacin, 2 g/ml; p-aminosalicylic acid, 4 g/ml; rifabutin, 0.5 g/ml. The Public Health Agency of Canada (PHAC) publishes yearly statistics on the antimicrobial resistance patterns of all laboratory-isolated Mycobacterium tuberculosis strains in Can-ada. From 2000 to 2010, the number of M. tuberculosis isolates resistant to one or more of the first-line antimicrobials has varied between 8.0 % and 11.0 % of all tuberculosis (TB) cases per year in Canada (15). Between 0.9 % and 1.6 % of these
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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 | 0.011 | 0.013 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.004 |
| Science and technology studies | 0.005 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.003 | 0.002 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.004 | 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".