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Molecular Analysis and Risk Factors for Escherichia coli Producing Extended-Spectrum ß-Lactamase Bloodstream Infection in Hematological Malignancies
Published: Monday, April 23, 2012
Author: Patricia Cornejo-Juárez et al.

by Patricia Cornejo-Juárez, Carolina Pérez-Jiménez, Jesús Silva-Sánchez, Consuelo Velázquez-Acosta, Fernanda González-Lara, Fernando Reyna-Flores, Alejandro Sánchez-Pérez, Patricia Volkow-Fernández


Patients with hematologic malignancies have greater risk-factors for primary bloodstream infections (BSI).


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.


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.


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.


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.