1. Division of Infectious Diseases, Institution of Medicine, Karolinska Institute, Huddinge University Hospital, 141 86 Stockholm
2. Department of Internal Medicine, Faculty of Medicine, Black Lion University Hospital, Addis Ababa, Ethiopia
3. Department of Microbiology and Immunology, The Gade Institute, Haukeland University Hospital, 5021 Bergen, Norway
4. Department of Bacteriology, Swedish Institute for Infectious Disease Control, 171 82 Solna, Sweden