[History of the changes in infectious diseases].

The spectrum of infectious diseases is not at all constant, it changes. This statement is relevant for the great epidemics as well as for nosocomial infections and simple infectious processes. The epidemiological situation of plague, lepra, cholera and diphtheria is discussed. As concerns nosocomial infections four periods are separated: the time before Semmelweis and Lister, the period of the introduction of antiseptic/aseptic measurements to the hospitals and the chemotherapy-time (period until 1965) and the time afterwards. The spectrum of nosocomial infections and its changes as observed in the Cologne area are presented. But also the types of a certain bacterial species are changing as discussed on the example of S. aureus phagetype 80/81. As far as known factors involved in these changes are mentioned. The increasing use of plastic materials in medicine (i.e. intravenous catheters, Spitz-Holtershunts, hipps, valves, etcetera) is the cause of infectious complications, S. epidermidis being the dominant organism.