[1] Natl Res Council Canada, Inst Biol Sci, Ottawa, ON K1A 0R6, Canada
[2] Erasmus Univ, Med Ctr, Dept Med Microbiol & Infect Dis, Rotterdam, Netherlands
[3] Karolinska Inst, Clin Res Ctr, S-14186 Huddinge, Sweden
[4] Univ Coll S Stockholm, Novum, S-14186 Huddinge, Sweden