Role of empirical and targeted therapy in hospitalized patients with bloodstream infections caused by ESBL-producing Enterobacteriaceae.

Backgroung: Bloodstream infection (BSI) due to extended-spectrum β-lactamase (ESBL) producingEnterobacteriaceae are a major cause of in-hospital mortality. The effect on survival of empirical andtargeted antibiotic therapy in these patients remains controversial.Methods: A prospective cohort study was conducted analyzing data from 94 patients (age 59 ± 21 years) withBSI due to ESBL producing strains (Sixty-one E. coli, 26 K. pneumoniae, 4 Proteus spp and 3 Enterobacterspp).Results: Risk factors associated with 21-day mortality at univariate analysis were: recent administration ofantibiotic therapy (p=0.049), higher SOFA score (p=0.05), ICU stay (p <0.01), hypotension at presentation(p =0.001) or septic shock (p <0.001) and bacteremia from source other than urinary tract (p=0.03).Regardless of antibiotic class used, no differences in survival were noted between patients receiving or notadequate initial antimicrobial treatment (37.1% vs 23.7% p=0.23); on the other hand, compared with theadministration of other in vitro active antibiotics, the use of carbapenem as definitive therapy was associatedwith a significantly lower 21-day mortality (54.3% vs 28.5% p=0.02).Conclusion: These findings suggest that the administration of an adequate initial therapy is not associatedwith mortality in hospitalized patients with BSI due to Enterobacteriaceae. The severity of clinical conditionsat presentation and the administration of carbapenems as definitive therapy seems to be really importantin affecting the outcome of patients with BSI due to ESBL producing strains