title: Antibiotic management of suspected nosocomial ICU-acquired infection: does prolonged empiric therapy improve outcome?
abstract: OBJECTIVE
  To characterize empiric antibiotic use in patients with suspected nosocomial ICU-acquired infections (NI), and determine the impact of prolonged therapy in the absence of infection.
  
  
  METHODS
  Multicenter prospective cohort, with eight medical-surgical ICUs in North America and Europe.
  
  
  METHODS
  195 patients with suspected NI.
  
  
  METHODS
  The diagnosis of NI was adjudicated by a blinded Clinical Evaluation Committee using retrospective review of clinical, radiological, and culture data.
  
  
  RESULTS
  Empiric antibiotics were prescribed for 143 of 195 (73.3%) patients with suspected NI; only 39 of 195 (20.0%) were adjudicated as being infected. Infection rates were similar in patients who did (26 of 143, 18.2%), or did not (13 of 52, 25.0%) receive empiric therapy (p = 0.3). Empiric antibiotics were continued for more than 4 days in 56 of 95 (59.0%) patients without adjudicated NI. Factors associated with continued empiric therapy were increased age (p = 0.02), ongoing SIRS (p = 0.03), and hospital (p = 0.004). Patients without NI who received empiric antibiotics for longer than 4 days had increased 28-day mortality (18 of 56, 32.1%), compared with those whose antibiotics were discontinued (3 of 39, 7.7%; OR = 5.7, 95% CI 1.5-20.9, p = 0.005). When the influence of age, admission diagnosis, vasopressor use, and multiple organ dysfunction was controlled by multivariable analysis, prolonged empiric therapy was not independently associated with mortality (OR = 3.8, 95% CI 0.9-15.5, p = 0.07).
  
  
  CONCLUSIONS
  Empiric antibiotics were initiated four times more often than NI was confirmed, and frequently continued in the absence of infection. We found no evidence that prolonged use of empiric antibiotics improved outcome for ICU patients, but rather a suggestion that the practice may be harmful.
authors.affiliation: University of Toronto, Interdepartmental Division of Critical Care Medicine and the Department of Surgery, Toronto, Canada.
authors.forename: Mary-Anne W
authors.initials: MA
authors.lastname: Aarts
authors.forename: Christian
authors.initials: C
authors.lastname: Brun-Buisson
authors.forename: Deborah J
authors.initials: DJ
authors.lastname: Cook
authors.forename: Anand
authors.initials: A
authors.lastname: Kumar
authors.forename: Steven
authors.initials: S
authors.lastname: Opal
authors.forename: Graeme
authors.initials: G
authors.lastname: Rocker
authors.forename: Terry
authors.initials: T
authors.lastname: Smith
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Vincent
authors.forename: John C
authors.initials: JC
authors.lastname: Marshall
mesh_terms: D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D015331:Cohort Studies; D003428:Cross Infection / Q000188:drug therapy*; D019049:Developed Countries; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D011446:Prospective Studies
chemical_list: D000900:Anti-Bacterial Agents