title: Surveillance cultures growing carbapenem-Resistant Acinetobacter baumannii predict the development of clinical infections: a retrospective cohort study.
abstract: BACKGROUND
  We aimed to determine the effect of the presence of carbapenem-resistant Acinetobacter baumannii in accordance with surveillance cultures on the subsequent development of clinical infections by this organism.
  
  
  METHODS
  This retrospective cohort study was conducted at a tertiary hospital from January 2010 to November 2011. We included all consecutive patients admitted to the trauma intensive care unit, who had weekly surveillance cultures performed (from rectum, and if intubated, respiratory secretions), and without evidence of A. baumannii infections prior to the collection of the first surveillance culture. Univariable and multivariable analyses were performed using log-binomial regression. Survival analyses were performed using Cox proportional hazards.
  
  
  RESULTS
  Three hundred sixty-four patients were included, of whom 49 (13.5%) had carbapenem-resistant A. baumannii on surveillance cultures. Patients with positive surveillance cultures had 8.4 (95% confidence interval [CI], 5.6-12.7; P < .0001) times the risk of developing a subsequent A. baumannii infection compared with patients who remained negative on surveillance cultures. Multivariable analysis showed significant associations between clinical infection and both positive surveillance cultures (relative risk [RR], 5.9 [95% CI, 3.8-9.3]; P < .0001) and mechanical ventilation (RR, 4.3 [95% CI, 1.03-18.2]; P = .05). On survival analyses, the only variable associated with the development of clinical infections was the presence of positive surveillance cultures (hazard ratio, 16.3 [95% CI, 9.1-29.1]; P < .001).
  
  
  CONCLUSIONS
  Presence of carbapenem-resistant A. baumannii on surveillance cultures is strongly associated with subsequent development of carbapenem-resistant A. baumannii infections. Prevention efforts should be focused at limiting the acquisition of this organism during hospitalization.
authors.affiliation: Department of Medicine.
authors.forename: Rachel
authors.initials: R
authors.lastname: Latibeaudiere
authors.affiliation: Department of Medicine.
authors.forename: Rossana
authors.initials: R
authors.lastname: Rosa
authors.affiliation: Department of Medicine.
authors.forename: Panthipa
authors.initials: P
authors.lastname: Laowansiri
authors.affiliation: Department of Public Health Sciences Division of Statistics.
authors.forename: Kristopher
authors.initials: K
authors.lastname: Arheart
authors.affiliation: Department of Surgery, University of Miami Miller School of Medicine, Florida.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Namias
authors.affiliation: Institute for Health and Society Department of Medicine, Medical College of Wisconsin, Milwaukee.
authors.forename: L Silvia
authors.initials: LS
authors.lastname: Munoz-Price
mesh_terms: D000151:Acinetobacter Infections / Q000453:epidemiology / Q000382:microbiology* / Q000517:prevention & control; D040981:Acinetobacter baumannii / Q000187:drug effects*; D000328:Adult; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D015780:Carbapenems / Q000494:pharmacology*; D015331:Cohort Studies; D024881:Drug Resistance, Bacterial; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D012121:Respiration, Artificial; D012189:Retrospective Studies; D062606:Tertiary Care Centers
chemical_list: D000900:Anti-Bacterial Agents; D015780:Carbapenems
keywords: Acinetobacter baumannii; carbapenem-resistant; clinical infections; intensive care unit; surveillance cultures