Research

Intensive care unit-acquired Stenotrophomonas maltophilia: incidence, risk factors, and outcome

Saad Nseir^1,2 , Christophe Di Pompeo², Hélène Brisson¹, Florent Dewavrin¹, Stéphanie Tissier¹, Maimouna Diarra¹, Marie Boulo¹ and Alain Durocher^1,2

¹Intensive Care Unit, Calmette Hospital, University Hospital of Lille, boulevard du Pr Leclercq, 59037 Lille cedex, France

²Medical Assessment Laboratory, Lille II University, 1 place de Verdun, 59045 Lille, France

author email corresponding author email

Critical Care 2006, 10:R143doi:10.1186/cc5063

Published:	6 October 2006

Abstract

Introduction

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).

Conclusion

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.