Molecular characterization of clostridium difficile isolated in Hong Kong SAR
Bibliographic record
Abstract
Background: Clostridium difficile is a common cause of pseudomenbranous colitis and more often, antibiotic-associated diarrhea, and remains the most common cause of nosocomial diarrhea (15-39%). In 2003, a nosocomial outbreak caused by a hypervirulent strain of C. difficile ribotype 027 was first identified in Quebec, Canada. This strain has now been documented in outbreaks across the US and European countries. The aim of this study was to characterize the toxigenic profile and genotype of C. difficile isolated from hospitalized patients in Hong Kong. Methods: At total of 204 isolates of C. difficile from diarrheal stool samples of hospitalized patients in Hong Kong during the period from January 2009 to December 2009 were recruited in this study. The presence of genes encoding toxin A (TcdA), toxin B (TcdB) and binary toxins (cdtA and cdtB) were detected by multiplex PCR. Single-locus sequence typing of the surface layer protein A gene (slpAST) was also performed for genotyping of these C. difficile isolates. Results: Amongst these 204 C. difficile isolates, 35 (17.16%) strains were found to be non-toxigenic, 151 (74.02%) strains were toxin A + B+, 4 (1.96%) strains possessed toxin A, B and binary toxins, and 5 (2,45%) strains were toxin A-B+. Using slpAST, most isolates were identified as PCR-ribotype 002 (32.8%). The second commonest C. difficile strain was og39 (7.8%), followed by ribotype 018 (5.9%), ribotype 010 (4.9%), ribotype 066 (4.9%), ribotype 014 (3.9%), ribotype 017 (2.9%), and ribotype 001 (2.0%). Conclusion: Ribotype 002 was the predominant genotype in Hong Kong and no ribotype 027 was detected in this study. Although molecular typing is not necessary for routine diagnosis, it is useful in epidemiology studies and recognizing the high-risk strain like ribotype 027 which would facilitate strategic infection control interventions especially during outbreak.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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) | 0.001 | 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".