P-1493. <i>In Vitro</i> Activity of Clindamycin in Comparison with Linezolid Versus <i>Streptococcus pyogenes</i> Clinical Isolates Recovered from Patients in Manitoba, Canada
Bibliographic record
Abstract
Abstract Background Clindamycin is often used in combination with a beta-lactam antimicrobial for the treatment of serious infections caused by Streptococcus pyogenes (e.g., necrotizing fasciitis, streptococcal toxic shock syndrome) due to its ability to suppress bacterial toxin synthesis. Of concern, increasing clindamycin resistance among S. pyogenes isolates has been reported in many parts of the world. The purpose of this study was to compare the in vitro activity of clindamycin with linezolid versus a contemporary Canadian collection of S. pyogenes clinical isolates. Methods S. pyogenes isolates from wounds and sterile body sites (one per patient) were obtained from three microbiology laboratories in Manitoba, Canada between December, 2022 and November, 2023. Susceptibility testing was performed by broth microdilution as described by CLSI, with MICs interpreted using current CLSI breakpoints. A D-test was set up for each isolate to investigate whether inducible clindamycin resistance was present. Results Susceptibility testing was performed on 140 S. pyogenes clinical isolates. The isolates were obtained from wound swabs (n = 71, 50.7%), sterile fluid/tissue samples (n = 27, 19.3%), and blood cultures (n = 42, 30.0%). All isolates were fully susceptible in vitro to penicillin and vancomycin. The proportion of isolates testing susceptible to clindamycin and linezolid was 82.9% and 100%, respectively. All of the clindamycin-resistant isolates demonstrated an inducible resistance phenotype (clindamycin MIC ≤0.12 ug/mL in all cases). Clindamycin susceptibility was similar for isolates from wound swabs (81.7%) and isolates from blood/sterile sites (84.1%). Conclusion The proportion of S. pyogenes isolates testing susceptible to clindamycin was 82.9%. All clindamycin resistant isolates demonstrated an inducible resistance phenotype. Further data are required to determine whether inducible clindamycin resistance is clinically relevant when clindamycin is used as adjunctive therapy (in combination with a beta-lactam) for serious S. pyogenes infections. All isolates tested remained susceptible to linezolid. Disclosures All Authors: No reported disclosures
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 distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".