Mortality risk factors for bloodstream infections caused by extended-spectrum beta-lactamase-producing microorganisms

Objective: To identify risk factors for mortality in patients with bloodstream infection by extended-spectrum beta-lactamase (ESBL)-producing microorganisms. Material and methods: A retrospective study in patients with bloodstream infection by ESBL-producing microorganisms from January 2000 to December 2006 was carried out. Results: A total of 4,172 bloodstream infections were identified, 1,218 (29.2%) and 226 (5.4%) of which were caused by Escherichia coli and Klebsiella pneumoniae, respectively. The overall mortality rate was 50.9% in patients with bacteriema due to ESBL-producing strains. The binomial logistic regression model, adjusted for age and severity, identified admission to an intensive care unit (OR 38,631; 95%CI:3,375-424,618; P = .002) and a SAPS II severity index score >30 in the 24-48 h before obtaining blood culture (OR 17,980; 95% CI:2,193-170,439; P = .010) as factors associated to mortality, while the urinary tract as primary site of infection was an independent determinant for non-mortality (OR 0.184; 95% 0:0.034-0.975; P = .047). Conclusions: Patients with suspicion of bacteriema who have been admitted to the ICU with a score of elevated severity should be candidates for early empirical treatments as they have a greater risk of mortality. However, the benefit of this strategy may be limited due to the baseline severity of the patient. (C) 2011 Elsevier Espana, S.L. All rights reserved.