Community-Acquired Severe Sepsis: A Prospective Cohort Study

Severe sepsis (SS) is one of the principal causes of admission in intensive care units (ICU), with an associated high morbidity and mortality. This study intends to characterize epidemiology of community-acquired SS (CASS) with special emphasis in the prevalence of multidrug resistant organisms and independent prognostic factors associated with ICU mortality. Methods: A prospective cohort study was conducted over 3.5 years, including all consecutive adult patients with CASS admitted to a mixed ICU, in a 600-bed university-affiliated hospital. Results: 1221 patients were admitted into the ICU, 25% with CASS. The mean age was 59 years and the mean SAPS (simplified acute physiological score) was II 48. Most had septic shock (67%). Respiratory (57%), intra-abdominal (22%) and urinary tract (8%) infections were the main sources of infection. The overall isolation rate was 56%. The most common identified microorganisms were Streptococcus pneumoniae (27%), Escherichia coli (22%), Staphylococcus aureus methicillin sensitive (8%) and Haemophilus influenzae (7%). The median ICU and hospital length of stay were 8 and 16 days, respectively. The ICU mortality rate was 33. Independent risk factors associated with higher mortality were older age, higher SAPS II, septic shock and chronic hepatic disease. Female gender was independently associated with lower mortality. The type of microorganism was not significantly associated with prognosis. Conclusion: CASS was highly prevalent among ICU admissions. Independent risk factors associated with ICU mortality included older age and previous comorbidities, but mainly severity of acute illness reinforcing the need for early recognition and treatment. Multidrug resistant organisms were implicated in considerable proportion of community-acquired sepsis.