Ammi Canada – Cacmid Annual Conference
Bibliographic record
Abstract
Clostridium difficile (CD) is responsible for the majority of antibioticassociated infections acquired at hospitals.Infected patients frequently shed CD spores into the environment, making it a major transmission factor and essential to its ability to cause outbreaks.Using high-resolution typing techniques (MMLVA), we found that strains isolated during outbreaks consisted of a main strain ('outbreak', with multiple identical isolates) and several sporadic strains.The outbreak strain was commonly of NAP1 type.Previous research focused on identifying markers of a 'hypervirulent' phenotype.However, because NAP1 strains are highly variable, we sought to determine markers of an 'outbreak' strains.Outbreak and sporadic strains from eight outbreaks were cultured until sporulation had occurred.Vegetative cells morphology and sporulation rates were documented by microscopy, while germination dynamics were estimated using Terbium fluorescence assay.No statistically significant difference in morphology, sporulation and germination of outbreak and non-outbreak strains was identified.Thus, we assessed other characteristics which might promote transmissibility of CD strains, such as spore adhesion and surface features as resolved by electron microscopy.Our data indicate that CD exosporium or spore crust can be responsible for adhesion of the spore to surfaces and its persistence in a hospital environment.Further studies of strains with mutated genes responsible for these features of CD spores should identify roles of these spore's components and assist with development of diagnostic tests to differentiate strains capable causing outbreaks from sporadic strains and develop effective measures of infection control to prevent transmission of this very important hospital-associated pathogen.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.003 | 0.001 |
| Scholarly communication | 0.005 | 0.001 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.003 | 0.002 |
| Insufficient payload (model declined to judge) | 0.425 | 0.131 |
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".