1. Department of Microbiology Tumor and Cell BiologyKarolinska InstituteStockholmSweden
2. Department of DermatologyUniversity Clinic Schleswig-HolsteinKielGermany
3. Swedish Institute for Infectious Disease ControlStockholmSweden
4. Institute for Medical Microbiology and Hospital EpidemiologyHannover Medical SchoolHannoverGermany