[Bacterial infections in intensive care units: etiology and pathogenesis].

Bacterial infections represent the main cause of morbidity and mortality in Intensive Care Units (ICU). The infections developed in ICU correspond to 24% of the overall nosocomial infections. Endogenous bacterial flora sustains 85% of infectious episodes. In fact in ICU cutaneous, oro-pharyngeal and gastro-intestinal flora are substantially modified being replaced by nosocomial microrganisms which will become responsible for sepsis and infections localized at respiratory and urinary tract. The Authors review these main diseases acquired in ICU analysing the epidemiologic features, pathogenesis, ways of transmission and diagnostic criteria. Finally it is underlined the importance of microbiology in any surveillance program of ICU acquired infections. It is desirable that each unit carries out an epidemiological evaluation by means of own microbiological data in order to establish, together with clinical epidemiologists and infectious diseases specialists, accurate programs of prevention.