Emergence and Characterization of Neisseria gonorrhoeae Isolates With Decreased Susceptibilities to Ceftriaxone and Cefixime in Canada
Bibliographic record
Abstract
BACKGROUND: Globally, Neisseria gonorrhoeae antimicrobial resistance has been increasing, and in particular, reports of isolates with reduced susceptibility to third-generation cephalosporins have surfaced. We examined the phenotypic and genetic characteristics of 155 N. gonorrhoeae isolates with decreased susceptibilities to third-generation cephalosporins isolated in Canada between 2001 and mid-2010. METHODS: Minimum inhibitory concentrations (MICs) were determined by agar dilution on N. gonorrhoeae isolates, and those displaying elevated MICs to cefixime (MIC = 0.25 μg/mL and 0.5 μg/mL) and ceftriaxone (MIC = 0.125 μg/mL and 0.25 μg/mL) were examined using N. gonorrhoeae multiantigen sequence typing (NG-MAST) and sequencing of resistance determinants associated with decreased cephalosporin susceptibilities (penA, mtrR, ponA, porB1b (penB alteration). RESULTS: Between 2001 and 2010, there has been a shift in the modal MICs from 0.016 to 0.125 μg/mL for cefixime and from 0.016 to 0.063 μg/mL for ceftriaxone. Thirty-seven different sequence types (STs) were identified among the isolates using N. gonorrhoeae multiantigen sequence typing; ST3158, ST225, and ST1407 were most prevalent at 25.9%, 19.4%, and 14.8%, respectively. The penA mosaic was present in 60% of the isolates, with the most common penA mosaic types XXXII and X identified at 51.0% and 7.7%, respectively, whereas the nonmosaic penA type XII was identified in 36.8% of the isolates. CONCLUSIONS: In Canada, N. gonorrhoeae isolates with decreased susceptibilities to third-generation cephalosporins have increased over the years. The alterations in penA, mtrR, and porB1b (penB alteration) are important determinants identified in these isolates. The most common STs identified among these Canadian isolates have also been reported worldwide.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 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".