1. Institute of Medical Microbiology, The 2nd Medical Faculty, Charles University,1 and
2. Institut für Hygiene und Mikrobiologie der Universität Würzburg, 97080 Würzburg, Germany2; and
3. Division of Microbiology, The Hospital for Sick Children, Toronto, Ontario M5G 1X8,3 and
4. National Laboratory for Enteric Pathogens, Laboratory Centre for Disease Control, Ottawa, Ontario K1A 0L2,4 Canada
5. 1st Clinic of Pediatrics, University Hospital Motol,5 150 06 Prague, Czech Republic;