The latter inclusion criterion for patients admitted in the emergency departments was defined by their case-history.Exclusion criteria were: a) HIV infection; b) neutropenia defined as an absolute neutrophil count lower than 1,000 neutrophils/mm3; or c) chronic intake of corticosteroids defined as any daily oral intake of 1 mg/kg or more of equivalent prednisone for more than one month. Patients with chronic obstructive pulmonary disease under systemic oral intake of corticosteroids were excluded from the study irrespective of the administered dose regimen.Sepsis was defined as the presence of a microbiologically documented or clinically diagnosed infection with at least two of the following [8]: a) core temperature above 38��C or below 36��C; b) heart rate of more than 90 beats per minute; c) respiratory rate of more than 20 breaths per minute or partial pressure of carbon dioxide below 32 mmHg; and d) leukocytosis (white blood cell count >12,000/mm3) or leukopenia (white blood cell count <4,000/mm3) or more than 10% bands in peripheral blood.Severe sepsis was defined as sepsis aggravated by the acute dysfunction of at least one organ due to tissue hypoperfusion [8]. Septic shock was defined as severe sepsis aggravated by systolic arterial pressure of less than 90 mmHg requiring administration of vasopressors [8].Acute pyelonephritis was diagnosed in every patient with all the following [9]: a) core temperature above 38��C or below 36��C; b) lumbar tenderness or radiological evidence consistent with the diagnosis of acute pyelonephritis; and c) 10 or more white blood cells per high-power field of spun urine or 2+ or more in dipstick test for white blood cells and nitrates.Community-acquired pneumonia (CAP) was diagnosed in every patient who was not hospitalized for the past 90 days and who was presenting with all the following [10]: a) core temperature above 38��C or below 36��C; b) white blood cell count of more than 12,000/mm3; and c) lobar consolidation in chest x-ray.Hospital-acquired pneumonia (HAP) was diagnosed in every patient who presented with the following signs at least 48 hours after admission and that were absent upon admission: a) new infiltrate in chest x-ray; and b) clinical pulmonary infection score of 6 or more as defined elsewhere [11].Ventilator-associated pneumonia (VAP) was diagnosed as HAP presenting in every patient intubated for more than two days with all the following [12-14]: a) core temperature above 38��C or below 36��C; b) purulent tracheobronchial secretions; and c) new chest x-ray infiltrates.