The Department of Infectious Diseases at the Robert Koch Institute studies bacterial and viral pathogens, the inactivation of microorganisms and immunological defence mechanisms against infection. Different microbiological pathogens and their properties are analysed by the individual working groups. This includes pathogen-specific characteristics that influence the spread of pathogens and diseases they induce, particularly with regard to changes in the pathogen and the development of new properties such as antibiotic-resistance. The department’s work is predominantly laboratory-oriented and involves both serological and molecular-biological aspects of the field. As well as studying the the properties of the pathogens the research groups also investigate the host’s susceptibility to infection and the ability of the immune system to control or eliminate the microorganisms. In addition, inactivation of infectious agents and aspects of hospital hygiene are studied in collaboration with other groups at the RKI. The working groups of the department are, like the project groups, supported by the use of imaging technologies, in particular electron microscopy.