title: Risk factors for and mortality of extended-spectrum-beta-lactamase-producing Klebsiella pneumoniae and Escherichia coli nosocomial bloodstream infections.
abstract: A case-control study, involving patients with positive blood cultures for Klebsiella pneumoniae (KP) or Escherichia coli (EC) EC and controls with positive blood cultures for non-ESBL-KP or EC, was performed to assess risk factors for extended-spectrum-beta-lactamase (ESBL) production from nosocomial bloodstream infections (BSIs). Mortality among patients with BSIs was also assessed. The study included 145 patients (81, 59.5% with K. pneumoniae and 64, 44.1% with E. coli BSI); 51 (35.2%) isolates were ESBL producers and 94 (64.8%) nonproducers. Forty-five (55.6%) K. pneumoniae isolates were ESBL producers, while only six (9.4%) E. coli isolates produced the enzyme. Multivariate analysis showed that recent exposure to piperacillin-tazobactam (adjusted Odds Ratio [aOR] 6.2; 95%CI 1.1-34.7) was a risk factor for ESBL BSI. K. pneumoniae was significantly more likely to be an ESBL-producing isolate than E. coli (aOR 6.7; 95%CI 2.3-20.2). No cephalosporin class was independently associated with ESBLs BSI; however, in a secondary model considering all oxymino-cephalosporins as a single variable, a significant association was demonstrated (aOR 3.7; 95%CI 1.3-10.8). Overall 60-day mortality was significantly higher among ESBL-producing organisms. The finding that piperacillin-tazobactam use is a risk factor for ESBL-production in KP or EC BSIs requires attention, since this drug can be recommended to limit the use of third-generation cephalosporins.
authors.affiliation: Laboratory of Microbiology, Hospital São Lucas, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil. silvanas@ufcspa.edu.br
authors.forename: Silvana Vargas
authors.initials: SV
authors.lastname: Superti
authors.forename: Gustavo
authors.initials: G
authors.lastname: Augusti
authors.forename: Alexandre Prehn
authors.initials: AP
authors.lastname: Zavascki
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D016470:Bacteremia / Q000382:microbiology / Q000401:mortality*; D001938:Brazil / Q000453:epidemiology; D016022:Case-Control Studies; D003428:Cross Infection / Q000382:microbiology / Q000401:mortality*; D024901:Drug Resistance, Multiple, Bacterial; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology; D004927:Escherichia coli Infections / Q000401:mortality*; D005260:Female; D006801:Humans; D007710:Klebsiella Infections / Q000378:metabolism / Q000401:mortality*; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000201:enzymology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D012307:Risk Factors; D015996:Survival Rate; D001618:beta-Lactamases / Q000096:biosynthesis*
chemical_list: D000900:Anti-Bacterial Agents; D001618:beta-Lactamases