We wish to thank Sonja Möller, Erik Louis Winzheim (Department of Infectious Diseases and Microbiology, University of Lübeck) and Silke Reinecke (Department of Microbial Drugs, Helmholtz Centre for Infection Research) for technical assistance. We also wish to thank Kathrin Wittstein for producing the material (Department of Microbial Drugs, Helmholtz Centre for Infection Research).

Funding: This work was supported by the German Center for Infection Research (DZIF, TTU HAARBI). Qiang Li was