title: Predictors of hospital mortality among septic ICU patients with Acinetobacter spp. bacteremia: a cohort study.
abstract: BACKGROUND
  We hypothesized that among septic ICU patients with Acinetobacter spp. bacteremia (Ac-BSI), carbapenem-resistant Acinetobacter spp. (CRAc) increase risk for inappropriate initial antibiotic therapy (non-IAAT), and non-IAAT is a predictor of hospital death.
  
  
  METHODS
  We conducted a retrospective cohort study of adult septic ICU patients with Ac-BSI. Non-IAAT was defined as exposure to initially prescribed antibiotics not active against the pathogen based on in vitro susceptibility testing, and having no exposure to appropriate antimicrobial treatment within 24 hours of drawing positive culture. We compared patients who died to those who survived, and derived regression models to identify predictors of hospital mortality and of non-IAAT.
  
  
  RESULTS
  Out of 131 patients with Ac-BSI, 65 (49.6%) died (non-survivors, NS). NS were older (63 [51, 76] vs. 56 [45, 66] years, p = 0.014), and sicker than survivors (S): APACHE II (24 [19, 31] vs. 18 [13, 22], p < 0.001) and Charlson (5 [2, 8] vs. 3 [1, 6], p = 0.009) scores. NS were also more likely than S to require pressors (75.4% vs. 42.4%, p < 0.001) and mechanical ventilation (75.4% vs. 53.0%, p = 0.008). Both CRAc (69.2% vs. 47.0%, p = 0.010) and non-IAAT (83.1% vs. 59.1%, p = 0.002) were more frequent among NS than S. In multivariate analyses, non-IAAT emerged as an independent predictor of hospital death (risk ratio [RR] 1.42, 95% confidence interval [CI] 1.10-1.58), while CRAc was the single strongest predictor of non-IAAT (RR 2.66, 95% CI 2.43-2.72).
  
  
  CONCLUSIONS
  Among septic ICU patients with Ac-BSI, non-IAAT predicts mortality. Carbapenem resistance appears to mediate the relationship between non-IAAT and mortality.
authors.forename: Andrew F
authors.initials: AF
authors.lastname: Shorr
authors.forename: Marya D
authors.initials: MD
authors.lastname: Zilberberg
authors.forename: Scott T
authors.initials: ST
authors.lastname: Micek
authors.forename: Marin H
authors.initials: MH
authors.lastname: Kollef
mesh_terms: D000150:Acinetobacter / Q000302:isolation & purification; D000151:Acinetobacter Infections / Q000188:drug therapy / Q000401:mortality*; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D016470:Bacteremia / Q000188:drug therapy / Q000401:mortality*; D015780:Carbapenems / Q000627:therapeutic use; D024881:Drug Resistance, Bacterial; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D012121:Respiration, Artificial; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index
chemical_list: D000900:Anti-Bacterial Agents; D015780:Carbapenems