Predictors of mortality in patients with bloodstream infections caused by extended-spectrum-beta-lactamase-producing Enterobacteriaceae: importance of inadequate initial antimicrobial treatment

Antimicrob Agents Chemother. 2007 Jun;51(6):1987-94. doi: 10.1128/AAC.01509-06. Epub 2007 Mar 26.

Abstract

Bloodstream infections (BSI) caused by extended-spectrum beta-lactamase (ESBL)-producing organisms markedly increase the rates of treatment failure and death. We conducted a retrospective cohort analysis to identify risk factors for mortality in adult in-patients with BSI caused by ESBL-producing Enterobacteriaceae (ESBL-BSI). Particular attention was focused on defining the impact on the mortality of inadequate initial antimicrobial therapy (defined as the initiation of treatment with active antimicrobial agents >72 h after collection of the first positive blood culture). A total of 186 patients with ESBL-BSI caused by Escherichia coli (n = 104), Klebsiella pneumoniae (n = 58), or Proteus mirabilis (n = 24) were identified by our microbiology laboratory from 1 January 1999 through 31 December 2004. The overall 21-day mortality rate was 38.2% (71 of 186). In multivariate analysis, significant predictors of mortality were inadequate initial antimicrobial therapy (odds ratio [OR] = 6.28; 95% confidence interval [CI] = 3.18 to 12.42; P < 0.001) and unidentified primary infection site (OR = 2.69; 95% CI = 1.38 to 5.27; P = 0.004). The inadequately treated patients (89 of 186 [47.8%]) had a threefold increase in mortality compared to the adequately treated group (59.5% versus 18.5%; OR = 2.38; 95% CI = 1.76 to 3.22; P < 0.001). The regimens most commonly classified as inadequate were based on oxyimino cephalosporin or fluoroquinolone therapy. Prompt initiation of effective antimicrobial treatment is essential in patients with ESBL-BSI, and empirical decisions must be based on a sound knowledge of the local distribution of pathogens and their susceptibility patterns.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Anti-Bacterial Agents / pharmacology*
  • Anti-Bacterial Agents / therapeutic use
  • Bacteremia / drug therapy
  • Bacteremia / microbiology
  • Bacteremia / mortality*
  • Cross Infection / drug therapy
  • Cross Infection / microbiology
  • Cross Infection / mortality
  • Drug Resistance, Bacterial
  • Enterobacteriaceae / drug effects*
  • Enterobacteriaceae / enzymology*
  • Enterobacteriaceae Infections / drug therapy
  • Enterobacteriaceae Infections / microbiology
  • Enterobacteriaceae Infections / mortality*
  • Escherichia coli / drug effects
  • Escherichia coli / enzymology
  • Female
  • Humans
  • Klebsiella pneumoniae / drug effects
  • Klebsiella pneumoniae / enzymology
  • Male
  • Microbial Sensitivity Tests
  • Middle Aged
  • Predictive Value of Tests
  • Proteus mirabilis / drug effects
  • Proteus mirabilis / enzymology
  • Risk Factors
  • Survival Analysis
  • Treatment Outcome
  • beta-Lactamases / biosynthesis*

Substances

  • Anti-Bacterial Agents
  • beta-Lactamases