If a patient is eligible, written, informed consent will be obtained either from the patient or, if the patient is incompetent via the patient's legal representative. Patients will be characterized clinically in terms of admission diagnosis, severity of illness (APACHE II), organ failures (SOFA) and final outcome (ICU and hospital mortality, death or survival 6 months following ICU admission. Date of death will be recorded when appropriate). Clinical status will be assessed daily for days 1, 2, 3, 5 and 7 of ICU admission using the Sepsis criteria, SOFA score, microbiological culture results and antibiotic therapy.