[Surveillance of nosocomial infections].

Exploratory and therapeutic hospital techniques, the frequency of iatrogenic or pathogenic immunodepression and the ever increasing age of the population are factors that augment the risk of nosocomial infections. Some of these infections are unavoidable, but others can be prevented. Appropriate hygienic measures and a rational use of antibiotics contribute to this prevention. We describe here two methods that can be used to watch for nosocomial infections. The one-day recording or prevalence survey method is meant to provide a snapshot image in a given hospital. Longitudinal supervision is more difficult to carry out, but it enables the situation to be more precisely evaluated in each health care centre. Supervision must be regarded as a descriptive stage in the assessment of the local situation as regards the prevalence and incidence of nosocomial infections. It should make it possible to determine priorities in the measures to be taken to prevent most of these infections.