Within-farm dynamics of ESBL/AmpC-producing Escherichia coli in veal calves: a longitudinal approach.

Objectives: To assess the within-farm dynamics of extended-spectrum β-lactamase (ESBL)/AmpC-producing Escherichia coli in veal calves.

Methods: Three veal-calf fattening farms were screened. Faecal samples from all calves within a compartment (109-150 per farm) were taken upon arrival on the farm (T0) and after 3, 6, 8 and 10 weeks (T3-T10).

Quantifying antimicrobial resistance at veal calf farms.

This study was performed to determine a sampling strategy to quantify the prevalence of antimicrobial resistance on veal calf farms, based on the variation in antimicrobial resistance within and between calves on five farms. Faecal samples from 50 healthy calves (10 calves/farm) were collected. From each individual sample and one pooled faecal sample per farm, 90 selected Escherichia coli isolates were tested for their resistance against 25 mg/L amoxicillin, 25 mg/L tetracycline, 0.