1. Department of Communicable Disease and Infection Control, Linköping University Hospital, SE-581 85 Linköping, Sweden
2. Department of Biomedical and Clinical Sciences, Linköping University, SE-581 85 Linköping, Sweden
3. Department of Clinical Microbiology, Linköping University Hospital, SE-581 85 Linköping, Sweden
4. Section of Clinical Microbiology, Department of Medical Sciences, Uppsala University, SE-751 85 Uppsala, Sweden