title: Intensive care unit-acquired Stenotrophomonas maltophilia: incidence, risk factors, and outcome.
abstract: BACKGROUND
  The aim of this study was to determine incidence, risk factors, and impact on outcome of intensive care unit (ICU)-acquired Stenotrophomonas maltophilia.
  
  
  METHODS
  This prospective observational case-control study, which was a part of a cohort study, was conducted in a 30-bed ICU during a three year period. All immunocompetent patients hospitalised >48 hours were eligible. Patients with non-fermenting Gram-negative bacilli (NF-GNB) at ICU admission were excluded. Patients without ICU-acquired S. maltophilia who developed an ICU-acquired NF-GNB other than S. maltophilia were also excluded. Screening (tracheal aspirate and skin, anal, and nasal swabs) for NF-GNB was performed in all patients at ICU admission and weekly. Univariate and multivariate analyses were performed to determine risk factors for ICU-acquired S. maltophilia and for ICU mortality.
  
  
  RESULTS
  Thirty-eight (2%) patients developed an S. maltophilia ICU-acquired colonisation and/or infection and were all successfully matched with 76 controls. Chronic obstructive pulmonary disease (COPD) and duration of antibiotic treatment (odds ratio [OR] [95% confidence interval (CI)] = 9.4 [3 to 29], p < 0.001, and 1.4 [1 to 2.3], p = 0.001, respectively) were independently associated with ICU-acquired S. maltophilia. Mortality rate (60% versus 40%, OR [95% CI] = 1.3 [1 to 1.7, p = 0.037]), duration of mechanical ventilation (23 +/- 16 versus 7 +/- 11 days, p < 0.001), and duration of ICU stay (29 +/- 21 versus 15 +/- 17 days, p < 0.001) were significantly higher in cases than in controls. In addition, ICU-acquired infection related to S. maltophilia was independently associated with ICU mortality (OR [95% CI] = 2.8 [1 to 7.7], p = 0.044).
  
  
  CONCLUSIONS
  COPD and duration of antibiotic treatment are independent risk factors for ICU-acquired S. maltophilia. ICU-acquired S. maltophilia is associated with increased morbidity and mortality rates. ICU-acquired infection related to S. maltophilia is an independent risk factor for ICU mortality.
authors.affiliation: Intensive Care Unit, Calmette Hospital, University Hospital of Lille, boulevard du Pr Leclercq, 59037 Lille cedex, France. s-nseir@chru-lille.fr
authors.forename: Saad
authors.initials: S
authors.lastname: Nseir
authors.forename: Christophe
authors.initials: C
authors.lastname: Di Pompeo
authors.forename: Hélène
authors.initials: H
authors.lastname: Brisson
authors.forename: Florent
authors.initials: F
authors.lastname: Dewavrin
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Tissier
authors.forename: Maimouna
authors.initials: M
authors.lastname: Diarra
authors.forename: Marie
authors.initials: M
authors.lastname: Boulo
authors.forename: Alain
authors.initials: A
authors.lastname: Durocher
mesh_terms: D016022:Case-Control Studies; D003428:Cross Infection / Q000453:epidemiology* / Q000401:mortality / Q000628:therapy; D016905:Gram-Negative Bacterial Infections / Q000453:epidemiology* / Q000401:mortality / Q000628:therapy; D006801:Humans; D015994:Incidence; D007362:Intensive Care Units; D011446:Prospective Studies; D012307:Risk Factors; D020615:Stenotrophomonas maltophilia; D016896:Treatment Outcome