Evaluation of clinical outcomes and risk factors associated with mortality in patients with Stenotrophomonas maltophilia bloodstream infection: a multicenter study

Background: Stenotrophomonas maltophilia, a pathogen that colonizes medical equipment and causes nosocomial infections due to its ability to form biofilms, has high mortality rates. This study investigated the risk factors related to mortality in patients who were diagnosed with S. maltophilia bacteremia. Methods: It is a multi-center, retrospective ad observational cohort study. The demographic characteristics, clinical findings, microbiological data, and risk factors for patients were obtained from the medical records of patients at ten different hospitals between January 1, 2018, and June 30, 2023. Results: The study included a total of 321 patients. The observed thirty-day mortality rate was 46.1%. A central venous catheter (CVC) was present in 276 patients (86%), and in 66 of these patients (23.9%) the CVC was removed. While only 18 patients (5.6%) received appropriate empirical antibiotics, 242 (75.4%) patients received appropriate antibiotics according to antimicrobial susceptibility test (AST) results and treatment revisions. Multivariate analysis revealed that advanced age (hazard ratio [HR] = 1.02; 95% confidence interval [CI]: 1.00– 1.03), appropriate antibiotic treatment (HR = 0.35; 95% CI: 0.23–0.52), and removal of central venous catheters (HR = 0.31; 95% CI: 0.16–0.60) were significantly related to reduced mortality. Conclusions: S. maltophilia is a significant pathogen, and to reduce its high mortality rate, removal of the CVC and switching to appropriate antibiotics should be performed as soon as possible.