title: [Clinical and molecular characterization of ESBL-producing enterobacteria isolated from bacteremia in a university hospital].
abstract: BACKGROUND
  Extended-spectrum-β-lactamases (ESBL) are plasmid-encoded enzymes that confer resistance to multiple antimicrobials. ESBL-producing enterobacteria that cause bacteremia limit therapeutic options and increase mortality.
  
  
  OBJECTIVE
  To perform a clinical and molecular description of bacteremia caused by ESBL-producing enterobacteria.
  
  
  METHODS
  We retrospectively studied the cases of bacteremia due to ESBL-producing Escherichia coli, Klebsiella pneumoniae and Proteus spp in adults admitted to a university hospital during the years 2004-2007. We reviewed the clinical records and antimicrobial susceptibility patterns. Molecular typing was performed by polymerase chain reaction and study of clonality by pulsed-field electrophoresis.
  
  
  RESULTS
  We found a prevalence of 9.8% ESBL in enterobacteria causing bacteremia. Decreased susceptibility to quinolones and aminoglycosides was observed, without resistance to carbapenems. The predominant ESBL types were CTX-M (96%), TEM (62%) and GES (28%). 79% of the strains presented more than one type of ESBL. Clinical analysis revealed high prevalence of risk factors, previous use of antimicrobials and of invasive devices. There was no significant clonality.
  
  
  CONCLUSIONS
  The presence of ESBLs in bloodstream infections is a clinical problem that must be considered when choosing empiric therapy.
authors.affiliation: Departamento de Laboratorios Cínicos, Pontificia Universidad Católica de Chile, Santiago, Chile. pgarcia@med.puc.cl
authors.forename: Patricia
authors.initials: P
authors.lastname: García C
authors.forename: Carla
authors.initials: C
authors.lastname: Rubilar P
authors.forename: Daniel
authors.initials: D
authors.lastname: Vicentini H
authors.forename: Juan C
authors.initials: JC
authors.lastname: Román G
authors.forename: Eugenia
authors.initials: E
authors.lastname: León C
authors.forename: Gabriel
authors.initials: G
authors.lastname: Muñoz C
authors.forename: Mariana
authors.initials: M
authors.lastname: Domínguez Y
authors.forename: Gerardo
authors.initials: G
authors.lastname: González R
authors.forename: Helia
authors.initials: H
authors.lastname: Bello T
authors.forename: Jaime
authors.initials: J
authors.lastname: Labarca L
mesh_terms: D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D016470:Bacteremia / Q000382:microbiology*; D016521:Electrophoresis, Gel, Pulsed-Field; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D004927:Escherichia coli Infections / Q000382:microbiology*; D006785:Hospitals, University; D006801:Humans; D007710:Klebsiella Infections / Q000382:microbiology*; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D008826:Microbial Sensitivity Tests; D016133:Polymerase Chain Reaction; D015995:Prevalence; D011511:Proteus / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D011512:Proteus Infections / Q000382:microbiology*; D012189:Retrospective Studies; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D001618:beta-Lactamases