1. These authors contributed equally to this paper
2. Bavarian Health and Food Safety Authority, Oberschleißheim, Germany
3. National Consiliary Laboratory for Diphtheria, Oberschleißheim, Germany
4. Division of Pediatric Infectious Diseases, Hauner Children's Hospital, Ludwig-Maximilians-University Munich, Munich, Germany
5. Department of Health and Environment, Munich, Germany
6. Max von Pettenkofer-Institute, Ludwig-Maximilians-University Munich, Munich, Germany