title: Clinical implications of extended spectrum beta-lactamase (ESBL) producing Klebsiella species and Escherichia coli on cefepime effectiveness.
abstract: OBJECTIVE
  To determine the affect of ESBL production among Klebsiella species and Escherichia coli on cefepime effectiveness.
  
  
  METHODS
  This was a retrospective, case-controlled study comparing the clinical and microbiologic responses of patients receiving cefepime for ESBL producing Klebsiella species or E. coli from a non-urine source with matched controls receiving cefepime for non-ESBL strains. Cases with ESBLs were included if they received monotherapy and were clinically evaluable. Non-ESBL controls were matched in a 2:1 ratio based on age, infection site, intensive care unit (ICU) stay, pathogen species and date of hospitalization.
  
  
  RESULTS
  Ten patients receiving cefepime for ESBLs were matched to 20 controls. Most patients received cefepime 1g q12h. Patients receiving cefepime for an ESBL infection were 9.7 (95% CI: 1.4-68.8) and 28.5 (95% CI: 2.6-306.6) times as likely to have an unsuccessful clinical and microbiological response compared with those with a non-ESBL infection. The presence of an ESBL did not have a statistically significant effect on all cause or infection-related mortality.
  
  
  CONCLUSIONS
  These data indicate that ESBL production among non-urinary Klebsiella species and E. coli negatively affected cefepime effectiveness. Further studies are required to evaluate if higher doses of cefepime may improve responses in ESBLs that are initially susceptible.
authors.affiliation: Center for Anti-Infective Research and Development, Hartford Hospital, 80 Seymour Street, Hartford, CT 06102-5037, USA.
authors.forename: Srividya
authors.initials: S
authors.lastname: Kotapati
authors.forename: Joseph L
authors.initials: JL
authors.lastname: Kuti
authors.forename: Charles H
authors.initials: CH
authors.lastname: Nightingale
authors.forename: David P
authors.initials: DP
authors.lastname: Nicolau
mesh_terms: D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use*; D016022:Case-Control Studies; D000077723:Cefepime; D002511:Cephalosporins / Q000494:pharmacology / Q000627:therapeutic use*; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects* / Q000201:enzymology; D004927:Escherichia coli Infections / Q000188:drug therapy* / Q000382:microbiology; D005260:Female; D006801:Humans; D007709:Klebsiella / Q000145:classification / Q000187:drug effects* / Q000201:enzymology; D007710:Klebsiella Infections / Q000188:drug therapy* / Q000382:microbiology; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D016896:Treatment Outcome; D001618:beta-Lactamases / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D000077723:Cefepime; D001618:beta-Lactamases