Distribution and Antibiotic Resistance of Stenotrophomonas maltophilia Isolates in a Tertiary Care Hospital in Türkiye: A Retrospective Study

Objective: This study aimed to retrospectively analyze the demographic characteristics of patients, clinical specimen types, and antibiotic susceptibility patterns of Stenotrophomonas maltophilia (S. maltophilia) isolates obtained in a tertiary care hospital in Türkiye between 2019 and 2025. Materials and Methods: A total of 443 S. maltophilia strains isolated from various clinical specimens between June 2019 and December 2025 were included in the study. Identification of the isolates and antibiotic susceptibility testing were performed using conventional methods and an automated system. Demographic and clinical data of the patients, along with antibiotic susceptibility results, were obtained from the hospital information system. Statistical analyses were conducted using SPSS version 22.0 and R version 3.3.2. Results: The number of isolates showed a fluctuating trend over the years, with the highest number recorded in 2022 (n = 94). The majority of isolates were obtained from intensive care units (71.3%), followed by inpatient wards (21.9%). Among clinical specimens, blood (42.7%) and tracheal aspirates (18.5%) were the most common. Significant temporal changes were observed in TMP–SMX susceptibility patterns. Fully susceptible isolates predominated in the early years, whereas intermediate susceptibility became increasingly common after 2021, while resistance rates remained relatively low throughout the study period. Conclusion: S. maltophilia remains an important nosocomial pathogen, particularly in intensive care patients and in association with invasive procedures. The observed changes in susceptibility patterns may affect treatment efficacy. Therefore, regular resistance surveillance, and consideration of local antibiograms are of great importance.