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Volume 31, Number 10—October 2025

Dispatch

Genetic Cluster of Extended-Spectrum β-lactamase–Producing Klebsiella pneumoniae in Humans and Food, Switzerland, 2018–2019

Lisandra Aguilar-Bultet1, Elena Gómez-Sanz1, Isabelle Vock, Monica Alt, Ruth Schindler, Laura Maurer Pekerman, Reto Furger, Lucas Eichenberger, Ingrid Steffen, Ana B. García-Martín, Tanja Stadler, Claudia Bagutti, and Sarah Tschudin-SutterComments to Author 
Author affiliation: University Hospital Basel, University of Basel, Basel, Switzerland (L. Aguilar-Bultet, E. Gómez-Sanz, I. Vock, R. Schindler, L. Maurer Pekerman, A.B. García-Martín, S. Tschudin-Sutter); Institute of Veterinary Bacteriology, Vetsuisse Faculty, University of Bern, Bern, Switzerland (E. Gómez-Sanz); State Laboratory Basel-City, Basel (M. Alt, R. Furger, L. Eichenberger, C. Bagutti); Rothen Laboratory, Basel (I. Steffen); ETH Zurich, Basel (T. Stadler); Swiss Institute of Bioinformatics, Basel (T. Stadler)

Main Article

Figure 1

Timeline showing history of isolate collection in detection of ESBL-producing Klebsiella pneumoniae in human and food samples, Switzerland, 2018–2019. Bold font indicates isolates in the Basel cluster. Clinical ESBL-producing K. pneumoniae sequence type 14 isolates were collected from patient A (isolate no. P0745) in May 2018 and from patient B (isolate no. P1134) in January 2019. Both patients were treated at the University Hospital Basel (Basel, Switzerland) but at different times and in different clinics (Appendix). Isolates P1134 and P0745 formed a mixed-cluster of ESBL-producing K. pneumoniae isolates with food isolate (F0067), which was collected from alfalfa cress in August 2018. Months with overlapping visits or stays between both patients are depicted in red, and reference numbers of different clinics are provided to assess spatial proximity. ED, emergency department; ESBL, extended-spectrum β-lactamase.

Figure 1. Timeline showing history of isolate collection in detection of ESBL-producing Klebsiella pneumoniae in human and food samples, Switzerland, 2018–2019. Bold font indicates isolates in the Basel cluster. Clinical ESBL-producing K. pneumoniae sequence type 14 isolates were collected from patient A (isolate no. P0745) in May 2018 and from patient B (isolate no. P1134) in January 2019. Both patients were treated at the University Hospital Basel (Basel, Switzerland) but at different times and in different clinics (Appendix). Isolates P1134 and P0745 formed a mixed-cluster of ESBL-producing K. pneumoniae isolates with food isolate (F0067), which was collected from alfalfa cress in August 2018. Months with overlapping visits or stays between both patients are depicted in red, and reference numbers of different clinics are provided to assess spatial proximity. ED, emergency department; ESBL, extended-spectrum β-lactamase.

Main Article

1These first authors contributed equally to this article.

Page created: August 20, 2025
Page updated: September 25, 2025
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