[1] Univ Med Ctr Utrecht, Dept Med Microbiol, Utrecht, Netherlands
[2] Hvidovre Univ Hosp, Dept Clin Microbiol, DK-2650 Hvidovre, Denmark
[3] Univ Copenhagen, Fac Hlth & Med Sci, Copenhagen, Denmark
[4] Univ Munster, Inst Hyg, D-48149 Munster, Germany
[5] Atrium Orbis Med Ctr, Dept Microbiol & Infect Prevent, Sittard, Netherlands
[6] Univ Helsinki, Dept Math & Stat, Helsinki, Finland
[7] Univ Munster, Dept Periodontol, D-48149 Munster, Germany