Clinical Characteristics and Prognostic Factors of Patients With Stenotrophomonas maltophilia Pneumonia: 10-Year Experience From a Single Center

Introduction: Stenotrophomonas maltophilia infection is gaining importance as an important cause of nosocomial pneumonia. S. maltophilia infection occurs especially in patients with a history of immunosuppression, comorbidity, or multiple antibiotherapy uses. A retrospective 10-year study was carried out to determine the clinical characteristics of all patients with S. maltophilia pneumonia, antibiotic resistance pattern, and risk factors associated with hospital mortality. Materials and methods: Hospitalized pneumonia patients with S. maltophilia culture positivity were identified, and their medical records were reviewed. Risk factors associated with hospital mortality were analyzed. Any variable with a significant association with mortality in the univariate analysis was entered in a multivariate forward stepwise logistic regression model to identify independent risk factors for death. Results: Seventy-two patients (mean age: 67.3 years, 65.2% males) with S. maltophilia pneumonia were included in the study. All patients had at least one comorbidity. The most common comorbidities were chronic obstructive pulmonary disease, diabetes mellitus, chronic renal failure, malignancy, and cardiac diseases. Percentage resistance to trimethoprim-sulfamethoxazole (5.5%) was lower than that for fluoroquinolones (12.5%). By using multivariate analysis, respiratory insufficiency needed mechanical ventilation, low hemoglobin level, age>65 years, previous antibiotic usage, and hypotension were the independent prognostic factors for mortality. Conclusion: S. maltophilia is emerging as an important pathogen with an increased risk of mortality in patients with respiratory insufficiency who need mechanical ventilation, a low hemoglobin level, >65 years of age, previous antibiotic usage, and hypotension. Empiric therapy should include agents active against S. maltophilia, such as newer fluoroquinolones and trimethoprim-sulfamethoxazole.