Antimicrobial‐Resistant <i>Streptococcus pneumoniae</i> in Canadian Hospitals: Results from the 2007 CANWARD Study
Bibliographic record
Abstract
BACKGROUND: The Canadian Ward Surveillance Study (CANWARD 2007) tested isolates collected from January to December 2007 from 12 Canadian hospitals to a range of antimicrobial agents. The present paper focuses on antimicrobial resistance in Streptococcus pneumoniae in Canadian hospitals, with an emphasis on macrolide resistance. MEtHODS: Minimum inhibitory concentrations of antimicrobial agents were determined using the broth microdilution method and interpreted according to Clinical and Laboratory Standards Institute breakpoints. Macrolide‐nonsusceptible strains (clarithromycin minimum inhibitory concentrations 0.5 μg/mL or greater) were analyzed by multiplex polymerase chain reaction for the presence of mefA and ermB genes. RESULTS: S pneumoniae represented 9.0% (706 of 7881) of all isolates collected in CANWARD 2007. Of the 706 S pneumoniae isolates collected, 33.1% (234) were from blood and 66.9% (472) were from respiratory specimens. The overall resistance (resistant and intermediate) rates for S pneumoniae isolated from respiratory and blood specimens, respectively, were: penicillin (23.9%, 14.4%), clarithromycin (22.1%, 12.6%), trimethoprim‐sulfamethoxazole (14.7%, 11.5%), doxycycline (7.8%, 5.1%) and clindamycin (7.1%, 3.3%). Multidrug resistance (resistance to penicillin, clarithromycin and trimethoprimsulfamethoxazole) accounted for 2% (n=9) and 0.5% (n=1) of respiratory and blood isolates, respectively. Susceptibility of 95% or greater was found with amoxicillin‐clavulanic acid (99.5%, 99.3%), ceftriaxone (99.5%, 100%), cefuroxime (95.0%, 96.8%), ertapenem (99.8%, 100%), meropenem (96.1%, 99.5%) and levofloxacin (99.1%, 100%) for respiratory and blood specimens, respectively. No resistance to vancomycin, tigecycline, cethromycin or telithromycin was found. mefA was present in 53.6% (52 of 97) of respiratory and 59.3% (16 of 27) of blood macrolide‐nonsusceptible S pneumoniae, while ermB was present in 38.1% (37 of 97) of respiratory and 37% (10 of 27) of blood isolates. Eight of 97 (8.2%) respiratory and one of 27 (3.7%) blood isolates contained both mefA and ermB genes. CONCLUSIONS: S pneumoniae is a common organism isolated from clinical specimens in Canadian hospitals. Resistance was highest to penicillin and clarithromycin, while ceftriaxone and levofloxacin susceptibility were both greater than 99%. No isolates resistant to vancomycin, tigecycline, linezolid or the ketolides were found. Resistance rates were higher among respiratory tract isolates of S pneumoniae than among blood isolates. Macrolide efflux, mefA, was the predominant mechanism of macrolide resistance among both respiratory and blood clarithromycin‐nonsusceptible isolates.
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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 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.005 |
| Science and technology studies | 0.003 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| 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".