Holger is an Associate Professor at the Department of Biomedicine, Health Faculty, Aarhus University in Denmark since 2011. His team works at the interface of microbial genomics, medical microbiology, and host-bacterium/microbiome interactions. He completed his Ph.D. thesis at the University of Göttingen, Germany, in 2003. He was a Postdoc at the Pasteur Institute, Paris, France, for 3 years, followed by a staff scientist position at the Max Planck Institute for Infection Biology, Berlin, Germany.