Characterization of Clostridioides difficile isolates recovered from two Phase 3 surotomycin treatment trials by restriction endonuclease analysis, PCR ribotyping and antimicrobial susceptibilities
Bibliographic record
Abstract
OBJECTIVES: To investigate the molecular epidemiology and antimicrobial susceptibility of Clostridioides difficile isolates from patients with C. difficile infection (CDI) from two Phase 3 clinical trials of surotomycin. METHODS: In both trials [Protocol MK-4261-005 (NCT01597505) conducted across Europe, North America and Israel; and Protocol MK-4261-006 (NCT01598311) conducted across North America, Asia-Pacific and South America], patients with CDI were randomized (1:1) to receive oral surotomycin (250 mg twice daily) or oral vancomycin (125 mg four times per day) for 10 days. Stool samples were collected at baseline and C. difficile isolates were characterized by restriction endonuclease analysis (REA) and PCR ribotyping. Susceptibility testing was performed by agar dilution, according to CLSI recommendations. RESULTS: In total, 1147 patients were included in the microbiological modified ITT population. Of 992 recovered isolates, 922 (92.9%) were typed. There was a high association between REA groups and their corresponding predominant PCR ribotype (RT) for BI, DH, G and CF strains. REA group A showed more diverse PCR RTs. Overall, the most common strain was BI/RT027 (20.3%) followed by Y/RT014/020 (15.0%) and DH/RT106 (7.2%). The BI/RT027 strain was particularly prevalent in Europe (29.9%) and Canada (23.6%), with lower prevalence in the USA (16.8%) and Australia/New Zealand (3.4%). Resistance was most prevalent in the BI/RT027 strain, particularly to metronidazole, vancomycin and moxifloxacin. CONCLUSIONS: A wide variation in C. difficile strains, both within and across different geographical regions, was documented by both REA and ribotyping, which showed overall good correlation.
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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 | 0.004 | 0.005 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".