Risk factors for mortality in Stenotrophomonas maltophilia bacteraemia: 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 analysed 43 cases of S. maltophilia bacteraemia 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), total parenteral nutrition ( 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 associated with improved survival ( P =0.005). These findings suggest that the SOFA score and CVC were associated with mortality in S. maltophilia bacteraemia and indicate that the effectiveness of antimicrobial therapy may depend on disease severity. The study underscores the potential need to implement diverse infection-control strategies to prevent S. maltophilia transmission and to tailor antimicrobial therapy to disease severity.