Bloodstream infections in adults: Importance of healthcare-associated infections

Objective: The objective of this study was to evaluate the characteristics of bloodstream infections occurring among outpatients having recent contact with the health care system compared to hospital and community-acquired infections. Methods: Prospective observational cohort study of adult patients with bloodstream infections at three teaching hospitals. Bloodstream infection was defined as hospital-acquired if the first positive blood culture was performed more than 48 h after admission. Other bloodstream infections were classified as healthcare-associated or community-acquired. Results: A total of 1157 episodes of bloodstream infections were studied; 581 (50.2%) were community-acquired, 295 (25.5%) were hospital-acquired, and 281 (24.3%) were health care-associated. Of the 281 health care-associated bloodstream infections, 68 (24%) occurred in patients residing in a nursing home, 104 (37%) in patients receiving intravenous therapy, health care at home, chemotherapy or attending dialysis, and 169 (60%) in patients hospitalized during the 90 days before their bloodstream infection (some patients belonged to more than one risk category). The highest prevalence rate of MRSA infections occurred in healthcare-associated infections (5%) (p < 0.001). A significantly higher mortality rate was seen in the group with healthcare-associated infections (27.5%) than in community-acquired infections (10.4%) (p < 0.001). Conclusions: Our results confirm that healthcare-associated bloodstream infections show important differences from community-acquired bloodstream infections and suggest that empirical antibiotic therapy should be similar to hospital-acquired bloodstream infections, taking into account the epidemiologic characteristics of each region. (C) 2007 The British Infection Society. Published by Elsevier Ltd. All rights reserved.