Risk Factors for Mortality in Stenotrophomonas maltophilia Bacteremia: A 22-Year Retrospective Study in a Japanese Acute Care Hospital

Stenotrophomonas maltophilia is a gram-negative bacterium associated with nosocomial infections and high mortality, although reported risk factors vary. We retrospectively analyzed 43 cases of S. maltophilia bacteremia at NTT Medical Center Tokyo (2002–2024). The overall mortality rate was 44.2%. Univariate analysis revealed that higher Sequential Organ Failure Assessment (SOFA) scores (p = 0.010), central venous catheterization (CVC; p = 0.028), intravenous hyperalimentation (p = 0.003), and diabetes mellitus (p = 0.033) were significantly associated with mortality. Multivariate analysis suggested SOFA score (p = 0.048) and CVC presence (p = 0.039) as independent risk factors. Appropriate antimicrobial therapy was not significantly associated with reduced overall mortality. However, it was associated with improved survival in patients with SOFA scores ≥5 (p = 0.029). Additionally, among patients with CVC, catheter removal was linked to better outcomes (p = 0.005). These findings suggest that the SOFA score and CVC use as key mortality risk factors in S. maltophilia bacteremia and indicate that antimicrobial therapy effectiveness may depend on disease severity. The study underscores a potential need to implement diverse infection control strategies to prevent S. maltophilia transmission and tailor antimicrobial therapy according to disease severity.