1. Max-von-Pettenkofer Institute; LMU Munich; Pettenkoferstr. 9a 80336 Munich Germany
2. German Center for Infection Research (DZIF); partner site LMU Munich; Munich Germany
3. Wernigerode Branch; Robert Koch Institute; Project Group 5, Burgstr. 37 38855 Wernigerode Germany
4. CNRS; Centre de Genetique Moleculaire Gif-sur-Yvette Cedex 91198 France