Clinical Impact of Rapid Identification (ID) and Phenotypic Antimicrobial Susceptibility Testing (AST) by Accelerate Pheno™ System (AXDX) for Gram-negative (GNB) Bloodstream Infections
Bibliographic record
Abstract
Laboratory turn-around-times (TATs) for identification (ID) and antimicrobial susceptibilities (AST) can delay prescription of adequate and/or optimal antimicrobial (ABX) therapy in septic patients leading to poor outcomes. The Accelerate Pheno™ system (Accelerate Diagnostics, USA) (AXDX) is a rapid ID and AST system with potential to improve TATs. Changes in Antibiotics Ordered for Gram-negative Bacilli Bloodstream Infections following Gram, ID, and AST Results. Time to Actual and Potential Antibiotic Tailoring Varying by ID and AST Method. 70 prospective non-duplicate blood cultures with Gram-negative bacilli were loaded onto AXDX. AXDX TATs were compared with TATs associated with current methods [ID by MALDI-TOF Vitek® MS (bioMérieux) using short-incubation plates, AST by Vitek® 2 (bioMérieux)]; modified current methods (calling MALDI ID and Vitek® 2 AST and releasing Vitek® 2 AST prior to purity plate review); and former methods (ID and AST by Vitek® 2), the latter determined by laboratory data review of 134 blood cultures from 2011. Impact of the change in TAT on ABX use was determined by chart review. Gram stain, ID and AST results led to tailoring of ABX in 88.6% of patients impacting 22.9%, 31.4%, and 64.3% of patients at 2.5h, 19.0h, and 62.1h respectively post positive blood culture using current methods (Figures 1 and 2). AXDX generated the shortest ID and AST TATs with the potential to shorten the time to ABX tailoring due to ID and AST to 1.3h and 6.7h respectively. Calling ID and AST results directly to physicians or releasing AST results from Vitek® 2 prior to purity plate review would also have the potential to significantly improve time to ABX change compared with current methods. Among the methods compared, AXDX has the greatest potential impact on time to appropriate antibiotics following reports of ID and AST results in Gram-negative bacilli bloodstream infections. Calling ID or AST results directly to physicians could also improve time to ABX tailoring. Impact of engaging antimicrobial stewardship teams requires further study. S. M. Poutanen, Accelerate Diagnostics: Research Contractor and Scientific Advisor, Consulting fee and Research support
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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 | 0.003 | 0.015 |
| 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 | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".