Prevalence and molecular characterization of clostridium difficile in veal calves and feedlot beef cattle
Notice bibliographique
Résumé
This research addressed for the first time the prevalence of ' Clostridium difficile' in a veal calf production unit and in feedlot beef cattle using a longitudinal design. For the veal farm study, rectal swabs were collected from 183 calves at arrival, as well as 1, 17 and 21 weeks later. Selective culture for ' C. difficile' was performed and the isolates recovered were characterized by PCR ribotyping, PCR for 'tcdA, tcdB, cdtA' and ' tet'(M) and E-test for tetracycline susceptibility. Overall, ' C. difficile' was isolated from 32% (56/174), 51% (88/172), 2% (4/183) and 2% (4/156) calves during successive samplings. Calves were two times more likely to test positive during the second sampling compared to the first sampling. The number of calves shedding 'C. difficile' was significantly lower after second sampling. Twelve different ribotypes were present at the first time point, and only three ribotypes at the second sampling. Ribotype 078 was the most common strain found. Close to 99% of the toxigenic strains isolated in the study have been identified in humans. There was a significant increase in tetracycline resistant isolates and in the number of bacteria carrying the 'tet'(M) gene. For the second study, four commercial feedlots in Alberta, Canada were enrolled. Fecal samples were collected at the time of arrival and shipping. Selective culture for 'C. difficile' was performed, and isolates were characterized by ribotyping and pulsed-field gel electrophoresis. A total of 543 cattle were enrolled. 'Clostridium difficile' was isolated from 3.3% of cattle at the time of arrival and from 5.5% at the time of shipping. Overall, there was no difference in the prevalence of ' C. difficile' shedding, however, on one of the farms, prevalence was higher at shipping. When only paired samples were evaluated, there was a significant difference in prevalence between arrival and exit in one of the four feedlots, as well as overall, with 'C. difficile' isolated from 2.1% at arrival and 5.5% at exit. All the isolates recovered were ribotype 078, a toxinotype V strain with genes encoding toxins A, B and CDT. In addition, all strains were classified as NAP7 by PFGE.
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 | 0,000 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,001 | 0,001 |
| 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) | 0,000 | 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 ».