[Epidemiologic surveillance in intensive care: how to organize it?].

Surveillance of nosocomial infections is the single most effective tool for nosocomial infection prevention. There are two main targets: a) prompt identification of indicators and epidemic events, in order to immediately start adequate interventions; b) comparison of local "own" experience to the nosocomial infections which would be expected in a population with similar clinical features. The microbiological laboratory is a reliable and economical source of information: it allows identification of "dangerous" microorganisms, monitoring of antimicrobial resistances, identification of epidemics due to a single agent. Active surveillance is necessary in every unit, in order to identify those specific indicators of infection, which are able to detect preventable events and which can be useful for "homogeneous" comparisons among ICUs. Accuracy (sensitivity and specificity) of identification methods and of case definition is of uttermost importance. It is equally important to collect patient data and care plan data targeted to document differences in type of treated patient and in type of level of care. A recent national survey among Italian public hospitals revealed a poor diffusion of surveillance: out of 428 responder hospitals, surveillance of epidemics and of antimicrobial resistance was active in less than 10%, surveillance in the unit was active in 15%, surveillance of sentinel pathogens was active in 22%.