title: Bacteremia due to extended-spectrum beta -lactamase-producing Escherichia coli in the CTX-M era: a new clinical challenge.
abstract: BACKGROUND
  Extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli, particularly those producing CTX-M types of ESBL, are emerging pathogens. Bacteremia caused by these organisms represents a clinical challenge, because the organisms are frequently resistant to the antimicrobials recommended for treatment of patients with suspected E. coli sepsis.
  
  
  METHODS
  A cohort study was performed that included all episodes of bloodstream infection due to ESBL-producing E. coli during the period from January 2001 through March 2005. Data on predisposing factors, clinical presentation, and outcome were collected. ESBLs were characterized using isoelectric focusing, polymerase chain reaction, and sequencing.
  
  
  RESULTS
  Forty-three episodes (8.8% of cases of bacteremia due to E. coli) were included; 70% of the isolates produced a CTX-M type of ESBL. The most frequent origins of infection were the urinary (46%) and biliary tracts (21%). Acquisition was nosocomial in 21 cases (49%), health care associated in 14 cases (32%), and strictly community acquired in 8 cases (19%). Thirty-eight percent and 25% of patients had obstructive diseases of the urinary and biliary tracts, respectively, and 38% had recently received antimicrobials. Nine patients (21%) died. Compared with beta-lactam/beta-lactamase-inhibitor and carbapenem-based regimens, empirical therapy with cephalosporins or fluoroquinolones was associated with a higher mortality rate (9% vs. 35%; P=.05) and needed to be changed more frequently (24% vs. 78%; P=.001).
  
  
  CONCLUSIONS
  ESBL-producing E. coli is a significant cause of bloodstream infection in hospitalized and nonhospitalized patients in the context of the emergence of CTX-M enzymes. Empirical treatment of sepsis potentially caused by E. coli may need to be reconsidered in areas where such ESBL-producing isolates are present.
authors.affiliation: Sección de Enfermedades Infecciosas, Hospital Universitario Virgen Macarena, Sevilla, 41071, Spain. jrb@nacom.es
authors.forename: Jesús
authors.initials: J
authors.lastname: Rodríguez-Baño
authors.forename: Maria D
authors.initials: MD
authors.lastname: Navarro
authors.forename: Luisa
authors.initials: L
authors.lastname: Romero
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Muniain
authors.forename: Marina
authors.initials: M
authors.lastname: de Cueto
authors.forename: María J
authors.initials: MJ
authors.lastname: Ríos
authors.forename: José R
authors.initials: JR
authors.lastname: Hernández
authors.forename: Alvaro
authors.initials: A
authors.lastname: Pascual
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019980:Amoxicillin-Potassium Clavulanate Combination / Q000627:therapeutic use; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016470:Bacteremia / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology*; D002511:Cephalosporins / Q000627:therapeutic use; D015331:Cohort Studies; D017714:Community-Acquired Infections / Q000188:drug therapy / Q000382:microbiology; D003428:Cross Infection / Q000188:drug therapy / Q000382:microbiology; D024901:Drug Resistance, Multiple, Bacterial; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D004927:Escherichia coli Infections / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology*; D005260:Female; D024841:Fluoroquinolones / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008875:Middle Aged; D010397:Penicillanic Acid / Q000031:analogs & derivatives / Q000627:therapeutic use; D010878:Piperacillin / Q000627:therapeutic use; D000077725:Piperacillin, Tazobactam Drug Combination; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D024841:Fluoroquinolones; D000077725:Piperacillin, Tazobactam Drug Combination; D019980:Amoxicillin-Potassium Clavulanate Combination; D010397:Penicillanic Acid; D001618:beta-Lactamases; D010878:Piperacillin