Molecular analysis and risk factors for Escherichia coli producing extended-spectrum β-lactamase bloodstream infection in hematological malignancies.

<h4>Introduction</h4>Patients with hematologic malignancies have greater risk-factors for primary bloodstream infections (BSI).<h4>Methods</h4>From 2004-2009, we analyzed bacteremia caused by extended-spectrum beta-lactamase Escherichia coli (ESBL-EC) (n = 100) and we compared with bacteremia caused by cephalosporin-susceptible E. coli (n = 100) in patients with hematologic malignancies.<h4>Objective</h4>To assess the clinical features, risk factors, and outcome of ESBL-EC BSI in patients with hematologic malignancies, and to study the molecular epidemiology of ESBL-EC isolates.<h4>Results</h4>The main diagnosis was acute leukemia in 115 patients (57.5%). Death-related E. coli infection was significantly increased with ESBL-EC (34% vs. control group, 19%; p = 0.03). Treatment for BSI was considered appropriate in 64 patients with ESBL-EC (mean survival, 245 ± 345 days), and in 45 control patients this was 443 ± 613 (p = 0.03). In patients not receiving appropriate antimicrobial treatment, survival was significantly decreased in cases compared with controls (26 ± 122 vs. 276 ± 442; p = 0.001). Fifty six of the ESBL-EC isolates were characterized by molecular analysis: 47 (84%) expressed CTX-M-15, two (3.6%) SHV, and seven (12.5%) did not correspond to either of these two ESBL enzymes. No TLA-1 enzyme was detected.<h4>Conclusions</h4>Patients who had been previously hospitalized and who received cephalosporins during the previous month, have an increased risk of ESBL-EC bacteremia. Mortality was significantly increased in patients with ESBL-EC BSI. A polyclonal trend was detected, which reflects non-cross transmission of multiresistant E.coli isolates.

Abstract licence: CC BY

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