Attributable mortality of nosocomial Acinetobacter bacteremia

Infect Control Hosp Epidemiol. 2007 Mar;28(3):293-8. doi: 10.1086/512629. Epub 2007 Feb 7.


Objective: To determine the attributable mortality and outcome of nosocomial Acinetobacter bacteremia.

Design: Matched, retrospective cohort study.

Setting: Large, university-based, tertiary care center.

Patients: Of 219 patients with nosocomial Acinetobacter bacteremia identified by prospective surveillance during a 3-year period, 52 met the criteria for the study and were matched to a control patient by age, sex, primary and secondary diagnosis, operative procedures, and date of admission.

Results: A 100% success rate was achieved in the proportion of case patients and control patients matched for the compared criteria, except for major operative procedures (88%) and the presence of an important secondary underlying disease (54.5%). Twenty-nine (55.7%) of the case patients died, compared with 10 (19.2%) of the control patients (P<.001). The attributable mortality was 36.5% (95% CI, 27%-46%) and the risk ratio for death was 2.9 (95% CI, 1.58-5.32). In a multivariate survival analysis, older age, mechanical ventilation, renal failure, and Acinetobacter bacteremia (hazard ratio [HR], 4.41; 95% confidence interval [CI], 1.97-9.87; P<.001) were found to be independent predictors of mortality. There was a trend for a longer median duration of hospitalization among case patients, compared with control patients (11.5 vs. 6.5 days; P=.06). Three isolates were resistant to all but 1 antibiotic tested (colistin), and 45 isolates (86.5%) were resistant to 4 or more different antibiotic classes.

Conclusions: When adjusted for risk-exposure time and severity of disease at admission, nosocomial Acinetobacter bacteremia is associated with mortality in excess of that caused by the underlying diseases alone.

MeSH terms

  • Acinetobacter / drug effects
  • Acinetobacter / isolation & purification*
  • Acinetobacter Infections / microbiology
  • Acinetobacter Infections / mortality*
  • Aged
  • Anti-Bacterial Agents / pharmacology
  • Bacteremia / microbiology
  • Bacteremia / mortality*
  • Case-Control Studies
  • Cross Infection / microbiology
  • Cross Infection / mortality*
  • Drug Resistance, Bacterial
  • Female
  • Hospital Mortality*
  • Humans
  • Length of Stay
  • Male
  • Microbial Sensitivity Tests
  • Middle Aged
  • Survival Analysis


  • Anti-Bacterial Agents