Risk factors associated with mortality of infections caused by Stenotrophomonas maltophilia: a systematic review.

The objective of this review was to assess the quality of available literature regarding risk factors associated with mortality of infections caused by S. maltophilia. PubMed and OVID were searched from March 1985 to March 2008, and eligible studies were considered to be those that related S. maltophilia infection with risk factors associated with mortality; described the characteristics of patients in detail; and provided data regarding the outcome and mortality. Thirty-eight studies were found referring to S. maltophilia (four with multivariate analysis and 10 with univariate analysis). This review has several limitations, mainly due to the heterogeneity of patients, lack of appropriate statistical analysis and lack of definition of nosocomial and community infection studies. Data reviewed suggest that infections caused by S. maltophilia have high mortality and that the risk factors associated with mortality are related to the initial clinical condition and patient type. Underlying haematological disease in cancer patients and admission to the intensive care unit are independent risk factors associated with mortality. Shock, thrombocytopenia and Acute Physiological Assessment and Chronic Health Evaluation (APACHE) score >15 are independent risk factors associated with outcome in patients with bloodstream infection and pneumonia. Organ dysfunction is the only independent risk factor associated with death from infection caused by sulfamethoxazole-resistant S. maltophilia. The impact of adequate antimicrobial therapy and removal of central venous catheter on mortality require further clinical studies.

Factors associated with mortality in patients with bloodstream infection and pneumonia due to Stenotrophomonas maltophilia.

Severe infections caused by Stenotrophomonas maltophilia are associated with high mortality, and strategies to improve the clinical outcome for infected patients are needed. A retrospective cohort study of patients with bloodstream infection (BSIs) and pneumonia caused by S. maltophilia was conducted. Multivariate analysis was performed to access factors associated with 14-day mortality. A total of 60 infections were identified. Among these, eight (13%) were pneumonias and 52 were BSIs; 33.3% were primary, 13% were central venous catheter (CVC)-related and 40% were secondary BSIs. Fifty-seven (85%) patients had received previous antimicrobial therapy; 88% had CVC, 57% mechanical ventilation and 75% were in the intensive care unit at the onset of infection. Malignancy (45%) was the most frequent underlying disease. The mean of the Acute Physiology and Chronic Health Evaluation II (APACHE II) scores was 17 and for the Sepsis-related Organ Failure Assessment (SOFA) score, it was 7 points. The overall and 14-day mortality were, respectively, 75% and 48%. Forty-seven (78%) patients were treated and, of these, 74% received trimethoprim-sulfamethoxazole. Independent risk factors associated with mortality were SOFA index >6 points (0.005) and septic shock (0.03). The Kaplan-Meier estimations curves showed that patients with APACHE II score >20 and SOFA score >10 had a survival chance of, respectively, less than 8% and less than 10% (P

Antimicrobial therapy for Stenotrophomonas maltophilia infections.

Stenotrophomonas maltophilia has emerged as an important nosocomial pathogen capable of causing respiratory, bloodstream, and urinary infections. The treatment of nosocomial infections by S. maltophilia is difficult, as this pathogen shows high levels of intrinsic or acquired resistance to different antimicrobial agents, drastically reducing the antibiotic options available for treatment. Intrinsic resistance may be due to reduced outer membrane permeability or to the multidrug efflux pumps. However, specific mechanisms of resistance such as aminoglycoside-modifying enzymes or the heterogeneous production of metallo-beta-lactamase have contributed to the multidrug-resistant phenotype displayed by this pathogen. Moreover, the lack of standardized susceptibility tests and their interpretative criteria hinder the choice of an adequate antibiotic treatment. Recommendations for the treatment of infections by S. maltophilia are based on in vitro studies, certain nonrandomized clinical trials, and anecdotal experience. Trimethoprim-sulfamethoxazole remains the drug of choice, although in vitro studies indicate that ticarcillin-clavulanic acid, minocycline, some of the new fluoroquinolones, and tigecycline may be useful agents. This review describes the main resistance mechanisms, the in vitro susceptibility profile, and treatment options for S. maltophilia infections.