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Antimicrobial resistance profiles of Escherichia coli and prevalence of extended-spectrum beta-lactamase-producing Enterobacteriaceae in calves from organic and conventional dairy farms in Switzerland
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  • Magdalena Nüesch-Inderbinen,
  • Claudia Hänni,
  • Sonja Hartnack,
  • Katrin Zurfluh,
  • Roger Stephan
Magdalena Nüesch-Inderbinen
University of Zurich

Corresponding Author:[email protected]

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Claudia Hänni
University of Zurich
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Sonja Hartnack
University of Zurich
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Katrin Zurfluh
University of Zurich
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Roger Stephan
University of Zurich
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This study compared the antimicrobial resistance (AMR) among commensal Escherichia coli in the fecal microbiota of young calves raised on organic and on conventional dairy farms in Switzerland. Further, fecal carriage of extended-spectrum beta-lactamase (ESBL) producing Enterobacteriaceae was assessed for calves from both farming systems. Where possible, data on antimicrobial usage (AMU) were obtained. Antimicrobial susceptibility testing was performed on a total of 71 isolates using the disk diffusion method. ESBL producers were characterized by PCR-based multilocus sequence typing and sequencing of the blaESBL genes. Organically raised calves were significantly more likely to harbor E. coli that showed antimicrobial resistance to ampicillin (OR 2.78, 95%CI 1.02–7.61, p=0.046), streptomycin (OR 3.22, 95%CI 1.17–8.92, p=0.046), kanamycin (OR 11.3, 95%CI 2.94–43.50, p<0.001), and tetracycline (OR 3.25, 95%, 95%CI 1.13–9.31, p=0.028). Calves with reported AMU were significantly more likely to harbor E. coli with resistance to ampicillin (OR 3.91, 95%CI 1.03–14.85, p=0.045), streptomycin (OR 4.35, 95%CI 1.13–16.7, p=0.045), and kanamycin (OR 8.69 95%CI 2.01–37.7, p=0.004). ESBL-producing Enterobacteriaceae (18 E. coli and 3 Citrobacter braakii) were detected exclusively among samples from conventionally farmed calves (OR infinity (∞), 95%CI 2.3–∞, p< 0.0013). The observations from this study suggest that AMR is highly prevalent among commensal E. coli in young dairy calves, irrespective of the farm management system, with proportions of certain resistance phenotypes higher among organic calves. By contrast, the occurrence of ESBL producers among young dairy calves may be linked to factors associated with conventional farming.
13 Dec 2021Submitted to MicrobiologyOpen
14 Dec 2021Submission Checks Completed
14 Dec 2021Assigned to Editor
16 Dec 2021Reviewer(s) Assigned
05 Jan 2022Review(s) Completed, Editorial Evaluation Pending
05 Jan 2022Editorial Decision: Revise Minor
24 Jan 20221st Revision Received
24 Jan 2022Submission Checks Completed
24 Jan 2022Assigned to Editor
24 Jan 2022Review(s) Completed, Editorial Evaluation Pending
24 Jan 2022Reviewer(s) Assigned
02 Feb 2022Editorial Decision: Revise Minor
06 Feb 20222nd Revision Received
07 Feb 2022Submission Checks Completed
07 Feb 2022Assigned to Editor
07 Feb 2022Review(s) Completed, Editorial Evaluation Pending
08 Feb 2022Editorial Decision: Accept