Epidemiological Study and Classification of ICU Infections, Using the Carrier State Criterion

This work aims at the better comprehension of epidemiology of ICU infections, using a classification based on the carrier state of the patient. This classification distinguishes the infections in primary endogenous (PE), secondary endogenous (SE) and exogenous (EX) infections. The material used was derived from ICU patients who were admitted to the ICU without being transferred from another ward of the same hospital or another hospital. Culture swabs were obtained from the pharynx and perineum of the patients at ICU admission and from then onwards every 3 days during their hospitalization. At the same time, cultures of clinical samples were carried out, on suspicion of infection. Ninety-six ICU patients were studied. In 31 of these, a total of 78 infections were developed. According to the proposed classification, 26 of the infections were PE (rate 33.3%), 34 SE (rate 43.6%) and 18 EX (rate 23.1%). Using the carrier state criterion, there were 11 fewer infections characterized as nosocomial (rate 14.1%), contrary to the 48-hour criterion. Based on this new taxonomy of infections, we are able to know in advance the source of the causative microorganisms and reduce the prevalence of ICU infections, by applying appropriate prevention and treatment strategies.