[1] Univ Regensburg, Inst Med Microbiol & Hyg, Regensburg, Germany
[2] Univ Zurich, Zurich, Switzerland
[3] Univ Strasbourg, Strasbourg, France
[4] Inst Biol Struct, Grenoble, France
[5] Univ Amsterdam, Acad Med Ctr, Amsterdam, Netherlands
[6] Sir William Dunn Sch Pathol, Oxford, England