title: Molecular analysis and risk factors for Escherichia coli producing extended-spectrum β-lactamase bloodstream infection in hematological malignancies.
abstract: BACKGROUND
  Patients with hematologic malignancies have greater risk-factors for primary bloodstream infections (BSI).
  
  
  METHODS
  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.
  
  
  OBJECTIVE
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Infectious Diseases, Instituto Nacional de Cancerología, Secretaría de Salud, Mexico City, Mexico. patcornejo@yahoo.com
authors.forename: Patricia
authors.initials: P
authors.lastname: Cornejo-Juárez
authors.forename: Carolina
authors.initials: C
authors.lastname: Pérez-Jiménez
authors.forename: Jesús
authors.initials: J
authors.lastname: Silva-Sánchez
authors.forename: Consuelo
authors.initials: C
authors.lastname: Velázquez-Acosta
authors.forename: Fernanda
authors.initials: F
authors.lastname: González-Lara
authors.forename: Fernando
authors.initials: F
authors.lastname: Reyna-Flores
authors.forename: Alejandro
authors.initials: A
authors.lastname: Sánchez-Pérez
authors.forename: Patricia
authors.initials: P
authors.lastname: Volkow-Fernández
mesh_terms: D000208:Acute Disease; D000328:Adult; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D004926:Escherichia coli / Q000201:enzymology* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000188:drug therapy / Q000382:microbiology* / Q000401:mortality; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D007938:Leukemia / Q000150:complications / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D001618:beta-Lactamases