Role of Clostridium Difficile in calf diarrhea and its potential implications to public health
Notice bibliographique
Résumé
The first study investigated the clinical significance of 'Clostridium difficile' in calf diarrhea and the relatedness between bovine and human 'C. difficile' PCR ribotypes. A retrospective case-control study involving 102 dairy farms in Ontario was performed with fecal samples from 134 diarrheic and 144 control calves. The isolation of 'Clostridium difficile' and the detection of its toxins A and B with a commercial ELISA test were conducted in a blinded fashion. 'Clostridium difficile ' was isolated from 31/278 calves; 11/144 (7.6%) with diarrhea and 20/134 (14.9%) controls (p=0.009). Toxins A or B, or both, were detected in feces from calves from 56.8% farms (58/102); 57/144 (39.6%) diarrheic calves and 28/134 (20.9%) controls (p=0.0002)PCR-ribotyping of 31 calf isolates revealed 8 distinct patterns; 7 identified in humans, of which, two have been associated with outbreaks of severe disease (PCR-types 017 and 027). In a second study, the potential causal association between ' C. difficile' and calf diarrhea was investigated with a prospective experimental infection study. Fourteen neonatal Holstein calves were inoculated with either a toxigenic strain of 'C. difficile' (PCR-type 077) (n=8) or placebo (n=6). Calves were monitored daily for signs of diarrhea, and were euthanized on day 6 or after the onset of diarrhea whichever came first. 'Clostridium difficile'-associated diarrhea was not recognized in the inoculated animals. Although 'C. difficile' PCR-type 077 was isolated from all infected calves, 'C. difficile' toxins were not consistently identified in feces using a commercial ELISA test. PCR-ribotyping analysis indicated that 4 calves under two days of age naturally harbored 5 different toxigenic 'C. difficile' ribotypes. Given the presence of 'C. difficile' spores in the feces of calves, a third study was conducted to investigate whether 'C. difficile ' could be cultured from commercial ground meat. The survival rate of spores treated at a cooking temperature (71°C) was also assessed. Sixty retail ground beef samples purchased in Ontario over a 10-month period were processed to identify 'C. difficile' spores. Toxigenic strains of 'C. difcile' were isolated from 20% (12/60) of the samples. PCR analysis showed 4 different ribotypes and similarity to human, bovine and canine ribotypes. Meat-derived 'Clostridium difficile' spores survived heating at 71°C. Although experimental oral infection of healthy calves with ' C. difficile' did not induce diarrhea within 6 days, this study indicates that 'C. difficile' is associated with calf diarrhea and that calves may be reservoirs of 'C. difficile' for humans. The PCR-ribotype similarity between bovine and human pathogenic isolates and the presence of 'C. difficile' spores in retail ground meat indicate that a risk of transmission between these two species might exist. The external validity of these epidemiological inferences needs further investigation.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,002 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,001 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».