Genetic diversity and antimicrobial resistance among isolates of Escherichia coli O157: H7 from feces and hides of super-shedders and low-shedding pen-mates in two commercial beef feedlots
Notice bibliographique
Résumé
BACKGROUND: Cattle shedding at least 104 CFU Escherichia coli O157:H7/g feces are described as super-shedders and have been shown to increase transmission of E. coli O157:H7 to other cattle in feedlots. This study investigated relationships among fecal isolates from super-shedders (n = 162), perineal hide swab isolates (PS) from super-shedders (n = 137) and fecal isolates from low-shedder (< 104 CFU/g feces) pen-mates (n = 496) using pulsed-field gel electrophoresis (PFGE). A subsample of these fecal isolates (n = 474) was tested for antimicrobial resistance. Isolates of E. coli O157:H7 were obtained from cattle in pens (avg. 181 head) at 2 commercial feedlots in southern Alberta with each steer sampled at entry to the feedlot and prior to slaughter. RESULTS: Only 1 steer maintained super-shedder status at both samplings, although approximately 30% of super-shedders in sampling 1 had low-shedder status at sampling 2. A total of 85 restriction endonuclease digestion clusters (REPC; 90% or greater similarity) and 86 unique isolates (< 90% similarity) were detected, with the predominant REPC (30% of isolates) being isolated from cattle in all feedlot pens, although it was not associated with shedding status (super- or low-shedder; P = 0.94). Only 2/21 super-shedders had fecal isolates in the same REPC at both samplings. Fecal and PS isolates from individual super-shedders generally belonged to different REPCs, although fecal isolates of E. coli O157:H7 from super- and low-shedders showed greater similarity (P < 0.001) than those from PS. For 77% of super-shedders, PFGE profiles of super-shedder fecal and PS isolates were distinct from all low-shedder fecal isolates collected in the same pen. A low level of antimicrobial resistance (3.7%) was detected and prevalence of antimicrobial resistance did not differ among super- and low-shedder isolates (P = 0.69), although all super-shedder isolates with antimicrobial resistance (n = 3) were resistant to multiple antimicrobials. CONCLUSIONS: Super-shedders did not have increased antimicrobial resistance compared to low-shedder pen mates. Our data demonstrated that PFGE profiles of individual super-shedders varied over time and that only 1/162 steers remained a super-shedder at 2 samplings. In these two commercial feedlots, PFGE subtypes of E. coli O157:H7 from fecal isolates of super- and low-shedders were frequently different as were subtypes of fecal and perineal hide isolates from super-shedders.
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Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,000 |
| 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 | 0,001 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,003 |
| 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 tête enseignante, 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 ».