Paper Information

We aimed to comprehensively assess Stenotrophomonas maltophilia infections, examining their incidence and clinical and microbiological characteristics in a tertiary hospital between 2021 and 2023. Primary outcomes were 30-day mortality and desirability-of-outcome ranking (DOOR). S. maltophilia incidence rose from 0.38 in 2017 to 2.66 cases/1000 patient-days in 2023, correlated with carbapenem consumption (rho = 0.90, p = 0.04). The cohort included 101 patients (median age of 61 years, IQR 43-71); 63% were male patients, 91% admitted in ICU, predominantly with lower respiratory tract infections (75%). Difficult-to-treat resistance (DTR) was identified in 14% of the isolates and associated with previous trimethoprim-sulfamethoxazole (TMP-SMX) use (aOR 23.15, 95% CI 3.67-145.77). Thirty-day mortality was 25% and associated with invasive mechanical ventilation (aOR 5.80, 95% CI 1.03-32.63), while appropriate definitive therapy was protective (aOR 0.01, 95% CI <0.01-0.16). Worse DOOR outcomes were associated with levofloxacin-resistant isolates (69.3%, CI 55.9%-80.9%) and inappropriate definitive treatment (81.1%, 95% CI 68.2%-90.8%). Overall, S. maltophilia has emerged as a relevant carbapenem-resistant gram-negative bacteria, with a high frequency of DTR phenotypes associated with previous TMP-SMX exposure. Appropriate therapy and levofloxacin susceptibility were linked to better outcomes.