• Vol. 37 No. 10, 826–830
  • 15 October 2008

Independent Predictors for Mortality in Patients with Positive Stenotrophomonas maltophilia Cultures



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Introduction: Stenotrophomonas maltophilia is an emerging pathogen in nosocomial infections that may result in high mortality. S. maltophilia often present as part of a polymicrobial culture and it is not well established when treatment is indicated. We aimed to identify predictors of mortality in patients with positive cultures of S. maltophilia.

Materials and Methods: A retrospective cohort study in a tertiary care medical centre was performed in 150 adult patients with positive cultures of S. maltophilia. Patients’ demographics, underlying diseases, severity of illness, length of hospitalisation, prior antibiotic exposure, number/types of indwelling catheters, culture sites, and appropriateness of empiric therapy were collected. Logistic regression was used to determine the independent risk factor(s) for infection-attributed mortality.

Results: Ninety-nine males and 51 females were studied. The mean (SD) age and APACHE II score of the patients were 61.9 (16.0) and 14.0 (6.1), respectively. The respiratory tract was the most frequent site (55.3%) where S. maltophilia was isolated. Infection-attributed mortality was observed in 22 of the 150 patients (14.7 %). Admission to ICU [Odds ratio (OR), 3.767; 95% confidence interval (CI), 1.277-11.116, P = 0.016], and delayed effective treatment (OR, 18.684; 95% CI, 4.050- 86.188; P <0.001) were identified as independent risk factors for mortality.

Conclusions: Predictors of mortality in patients with positive cultures of S. maltophilia were identified, which may guide clinicians in patient assessment and devising therapeutic decisions. Further studies are needed to validate our results.

Stenotrophomonas (formally Pseudomonas or Xanthomonas) maltophilia is a gram-negative bacillus emerging as an opportunistic, nosocomial pathogen associated with a high mortality rate. Although it was previously considered to have limited pathogenicity, recent reports suggested that infection with S. maltophilia was associated with significant morbidity and mortality, particularly in severely immunocompromised and clinically debilitated patients.

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