RISK FACTORS ASSOCIATED WITH MORTALITY IN NOSOCOMIAL STENOTROPHOMONAS MALTOPHILIA PNEUMONIA: A SINGLE-CENTER RETROSPECTIVE STUDY-

Objectives
Stenotrophomonas maltophilia (S. maltophilia) is a multidrug-resistant pathogen frequently isolated in hospital-acquired pneumonia and represents a significant clinical challenge. This study aimed to investigate the risk factors associated with 30-day mortality in patients diagnosed with S. maltophilia pneumonia.

Methods
This retrospective, single-center study included patients aged 18 years and older who were hospitalized between January 2018 and December 2021, had S. maltophilia isolated from respiratory samples, and demonstrated clinical and radiological evidence of pneumonia. Patients were grouped based on 30-day survival status, and comparisons were made concerning demographic characteristics, risk factors, and antibiotic regimens.

Results
Of 200 evaluated patients, colonization was noted in 48%. A total of 104 patients met inclusion criteria, with 75% requiring ICU admission. The 30-day mortality rate was 55.7%. Solid organ malignancies were present in 37.5%, and hematological malignancies in 25%. Polymicrobial infections and coinfections were observed in 39.4% and 82.4%, respectively. Multivariate analysis identified hematologic malignancy (OR = 4.215, 95% CI [1.316–13.495], p = 0.015), mechanical ventilation (OR = 6.394, 95% CI [2.096–19.505], p = 0.001), and a high Charlson Comorbidity Index (OR = 1.283, 95% CI [1.063–1.550], p = 0.009) as independent predictors of mortality. The use of combination antibiotic therapy had no significant effect on mortality. No resistance to trimethoprim-sulfamethoxazole was detected.

Conclusion

S. maltophilia pneumonia is a serious nosocomial infection with high mortality, particularly in ICU patients with malignancies. Hematologic malignancy, mechanical ventilation, and a high Charlson Comorbidity Index were independently associated with increased mortality.