1. These authors contributed equally to this work
2. French Institute for Public Health Surveillance (Institut de Veille Sanitaire; InVS), Regional office ‘Cire Aquitaine’, Bordeaux, France
3. Bordeaux University Hospital, Bordeaux, France
4. Institut Pasteur, National Reference Centre for Escherichia coli and Shigella, Paris, France
5. Robert Debré Hospital, Associated Laboratory to the National Reference Centre for Escherichia coli and Shigella, Paris, France
6. Robert Picqué Military Hospital, Villenave-D’Ornon, France
7. Regional Health Agency of Aquitaine, Bordeaux, France
8. Both authors contributed equally to this work