oF old doGs and new TriCks: The Epidemic of Hyper-virulent Clostridium difficile Infection
Bibliographic record
Abstract
Clostridium difficile (CD) has been a well-recognized cause of antibiotic-associated diarrheal disease since the late 1970’s. A mutation in toxin gene regulation, however, has unleashed a new epidemic of hyper-virulent infection. This new strain of CD, designated B1/NAP1/027, has spread rapidly across North America, Europe, and Asia, and has now supplanted Methicillin-Resistant Staphylococcus Aureus (MRSA) as the leading cause of nosocomial infection in some U.S. hospitals. This paper highlights the changing epidemiologic and clinical features of this born-again pathogen, and discusses new approaches to the diagnosis, treatment, and prevention of modern era Clostridium difficile infection (CDI). SCOPE AND IMPACT OF CDI Toxin-producing strains of CD were first linked to cases of antibiotic-associated diarrhea in 1978. By the year 2000, CDI was known to cause 15-25% of cases of diarrhea associated with the use of antibiotics, particularly in hospital settings. In Quebec in 2003, an outbreak of severe diarrheal disease with high morbidity and mortality due to CD was described. 1 The incidence of CDI there quadrupled, and was associated with an unusually high attributable mortality of 6.9%, compared with a baseline of 1.5%. Outbreaks in the U.S. quickly followed. Subsequent analysis of microbial samples from Quebec as well as from six U.S. east coast states demonstrated the clonal nature of the outbreak strain, subsequently dubbed the North American Pulsed Field type 1 (NAP1) strain of CD. 2 Other designations for this same strain include restriction endonuclease strain B1, and PCR ribotype 027 (or simply B1/NAP1/027). Since 1996, the incidence of CDI in the U.S. has more than doubled, with an estimated 3 million cases each year. Thus CDI in now possibly the most common identified bacterial cause of acute diarrhea in the U.S. 3 The total estimated cost (in 2005 dollars) of care for patients with CDI exceeds $3.2 billion. 4 In a
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.002 | 0.002 |
| Scholarly communication | 0.003 | 0.002 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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".