In Vitro Activity of Colistin (Polymyxin E) Versus 2541 Pseudomonas aeruginosa Clinical Isolates Obtained From Patients in Canadian Hospitals: Results of the CANWARD Study, 2008–2014
Bibliographic record
Abstract
Background. Clinicians have limited therapeutic options from which to choose for the treatment of infections caused by multidrug-resistant (MDR) Pseudomonas aeruginosa (MDR = non-susceptible to at least one antimicrobial from three or more different classes). Colistin, a polymyxin antimicrobial, is sometimes used as an agent of last resort. The purpose of this study was to evaluate the in vitro activity of colistin (polymyxin E) against a large collection of P. aeruginosa clinical isolates obtained from patients in Canadian hospitals (CANWARD, 2008 to 2014). Methods. From January 2008 to December 2014, inclusive, 10 to 15 sentinel hospitals across Canada submitted clinical isolates from patients attending ERs, medical and surgical wards, hospital clinics, and ICUs (CANWARD). Each center was asked to submit clinical isolates (consecutive, one per patient/infection site) from blood (100 to 240), respiratory (100 to 150), urine (25 to 100), and wound (25 to 100) infections. Susceptibility testing was performed using broth microdilution as described by CLSI. Results. The in vitro activity of colistin and comparator antimicrobials was evaluated versus 2541 P. aeruginosa clinical isolates (table below). Three-hundred and seventy-one isolates (14.6% of all isolates tested) were MDR. Of these, 92.2% were susceptible to colistin. Among 140 colistin non-susceptible isolates (5.5% of all isolates tested), 79.3% remained fully susceptible to antimicrobials from three or more antipseudomonal antimicrobial classes. Conclusion. Colistin demonstrated potent in vitro activity against P. aeruginosa clinical isolates, including those with an MDR phenotype. Isolates that were non-susceptible to colistin typically remained susceptible to multiple other antipseudomonal antimicrobials, indicating a lack of cross resistance. Disclosures. D. Hoban, Abbott: research relationship, Research support Achaogen: research relationship, Research support. Affinium: research relationship, Research support. AstraZeneca: research relationship, Research support. Astellas: research relationship, Research support. Cerexa: research relationship, Research support. Cubist: research relationship, Research support. Galderma: research relationship, Research support. Janssen Ortho Inc: research relationship, Research support. Merck: research relationship, Research support. Novexel: research relationship, Research support. Paladin Labs: research relationship, Research support. Pfizer: research relationship, Research support. Pharmascience Inc: research relationship, Research support. Sunovion: research relationship, Research support. Targanta: research relationship, Research support. Tetraphase: research relationship, Research support. The Medicines Company: research relationship, Research support. Theravance: research relationship, Research support. Wyeth: research relationship, Research support. Zoetis: research relationship, Research support; G. Zhanel, Abbott: research relationship, Research support. Achaogen: research relationship, Research support. Affinium: research relationship, Research support. Astellas: research relationship, Research support. AstraZeneca: research relationship, Research support. Cerexa: research relationship, Research support. Cubist: research relationship, Research support. Galderma: research relationship, Research support. Janssen Ortho Inc: research relationship, Research support. Merck: research relationship, Research support. Merck: research relationship, Research support. Novexel: research relationship, Research support. Paladin Labs: research relationship, Research support. Pfizer: research relationship, Research support. Pharmascience Inc: Research relationship, Research support. Sunovion: research relationship, Research support. Targanta: research relationship, Research support. Tetraphase: research relationship, Research support. The Medicines Company: research relationship, Research support. Theravance: research relationship, Research support. Wyeth: research relationship, Research support. Zoetis: research relationship, 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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.003 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".