EPIDEMIOLOGIC INVESTIGATION OF <em>CLOSTRIDIUM DIFFICILE</em> AND <em>CLOSTRIDIUM PERFRINGENS</em> IN HEALTHY HORSES
Bibliographic record
Abstract
Clostridium difficile and Clostridium perfringens are important causes of equine colitis but can also be found in healthy individuals. Epidemiologic information is restricted to cross-sectional studies of fecal shedding with little information on prevalence in gastrointestinal compartments other than feces and variability in shedding over time. The objectives were to investigate the presence of C. difficile and C. perfringens in healthy horses over time and assess prevalence in different gastrointestinal compartments. Feces were collected monthly from 25 horses for one year. Ingesta were collected from nine GI compartments of a separate group of 15 euthanized horses. Selective enrichment culture was performed, followed by toxin gene detection and ribotyping (C. difficile) and multiplex PCR (C. perfringens). Toxigenic C. difficile was isolated from 15/275 (5.5%) samples from 10/25 (40%) horses over one year. Three horses were positive in consecutive months, but different ribotypes were found in 2/3. Ribotypes included 078 (n=6), 001 (n=5) and an A+B+CDT+ ribotype previously identified as toxinotype IX in this laboratory (n=4). C. perfringens was not recovered despite a detection threshold of 9cfu/g feces. Toxigenic C. difficile was isolated from 14/135 (10.3%) ingesta samples from 8/15 (50.3%) horses, from both the small and large intestine. Multiple compartments were positive in four horses but more than one ribotype was present in all. In 3/8 colonized horses (38%) the rectal sample was negative but a proximal site was positive. Ribotypes included 078 (n=5), 001 (n=4) and three A+B+CDT- ribotypes not previously identified in this laboratory. C. perfringens type A (CPE- and ß2-) was recovered from the colon of 1/15 horses (6.6%). In the longitudinal study only one horse shed the same strain for more than one month, suggesting horses are short-term carriers or that C. difficile spores are passively moving through the intestinal tract. The presence of multiple ribotypes in different gastrointestinal compartments in the same horse further supports transient passage. Agreement between feces and proximal compartments was moderate to good (¿=0.61), suggesting limitations with studies using feces. The predominance of ribotype 078, in contrast to earlier reports, suggests recent emergence in this horse population, similar to reports from humans. The low prevalence of C. perfringens supports results of previous studies that indicate this organism is rare in healthy horses.
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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 | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| 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".