title: Health and economic outcomes of the detection of Klebsiella pneumoniae-produced extended-spectrum beta-lactamase (ESBL) in a hospital with high prevalence of this infection.
abstract: BACKGROUND
  Klebsiella pneumoniae is of high prevalence in hospital infections, mainly in bloodstream infections (BSI), and some produce extended-spectrum beta-lactamase (ESBL). For hospitals with a high prevalence of strains producing this enzyme, there is no reference material to show whether the use of the E-test method for their detection, which can be quite expensive, is actually required.
  
  
  OBJECTIVE
  To evaluate the cost-benefit of the disk diffusion and E-test methods for the detection of ESBL-producing K. pneumoniae strains in hospitals where a high prevalence of this resistance mechanism in BSI is found.
  
  
  METHODS
  One hundred and eight patients with K. pneumoniae BSI were evaluated retrospectively. ESBL-producing strains were identified by the disk diffusion method and by the E-test method. We estimated the costs of both diagnostic methods based on antimicrobial therapy adequacy.
  
  
  RESULTS
  Fifty-two percent of K. pneumoniae infections were due to ESBL-producing strains. The disk diffusion method yielded a positive predictive value (PPV) of 94.7% (95% CI: 88.9-100%) and a negative predictive value (NPV) of 96.1% (CI 95%: 90.8-101.4%) in relation to the E-test. We evaluated cost-effectiveness, i.e., we analyzed the cost of both E-test and disk diffusion methods with carbapenem and cephalosporins, and found that the use of the disk diffusion method accounts for approximately US$3300.
  
  
  CONCLUSIONS
  In hospitals with a high prevalence of ESBL-producing strains, the disk diffusion method can be used to detect ESBL-producing K. pneumoniae without compromising the clinical progression of patients with BSI. The E-test showed higher accuracy but this method was more expensive than the disk diffusion method. However, the use of the E-test method was demonstrated to be more cost-effective, as we evaluated cost based on antimicrobial therapy adequacy.
authors.affiliation: Universidade Federal de São Paulo, Escola Paulista de Medicina, Disciplina de Doenças Infecciosas e Parasitárias, Rua Botucatu, 743, 7 andar, Vila Clementino, CEP 04023-062, São Paulo, SP, Brazil. a.marra@uol.com.br
authors.forename: A R
authors.initials: AR
authors.lastname: Marra
authors.forename: C A P
authors.initials: CA
authors.lastname: Pereira
authors.forename: A
authors.initials: A
authors.lastname: Castelo
authors.forename: J R
authors.initials: JR
authors.lastname: do Carmo Filho
authors.forename: R G R
authors.initials: RG
authors.lastname: Cal
authors.forename: H S
authors.initials: HS
authors.lastname: Sader
authors.forename: S B
authors.initials: SB
authors.lastname: Wey
mesh_terms: D000046:Academic Medical Centers; D000328:Adult; D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use; D016470:Bacteremia / Q000175:diagnosis / Q000188:drug therapy / Q000191:economics*; D001938:Brazil; D015780:Carbapenems / Q000494:pharmacology / Q000627:therapeutic use; D002511:Cephalosporins / Q000494:pharmacology / Q000627:therapeutic use; D015331:Cohort Studies; D003365:Costs and Cost Analysis; D006761:Hospitals; D006801:Humans; D007710:Klebsiella Infections / Q000175:diagnosis / Q000188:drug therapy / Q000191:economics*; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000201:enzymology*; D008826:Microbial Sensitivity Tests; D012189:Retrospective Studies; D016896:Treatment Outcome; D001618:beta-Lactamases / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D015780:Carbapenems; D002511:Cephalosporins; D001618:beta-Lactamases