[1] Norwegian Inst Publ Hlth, Div Infect Dis Control, N-0403 Oslo, Norway
[2] Univ Oslo, Rikshosp, Radiumhosp Med Ctr, Inst Med Microbiol, N-0027 Oslo, Norway
[3] Norwegian Univ Sci & Technol, Dept Lab Med Childrens & Womens Hlth, N-7034 Trondheim, Norway
[4] Univ Trondheim Hosp, St Olavs Hosp, Dept Microbiol, Trondheim, Norway
[5] Haukeland Univ Hosp, Dept Microbiol & Immunol, N-5021 Bergen, Norway
[6] Univ Hosp N Norway, Dept Microbiol & Infect Control, Tromso, Norway
[7] Ullevaal Univ Hosp, Dept Microbiol, Oslo, Norway
[8] Univ Oslo, Oslo, Norway