Predictors of Candida auris Infection in Previously Colonized Patients: A Retrospective Cohort Study from a Large Tertiary Reference Center

Candida auris is a multidrug-resistant fungal pathogen associated with high mortality in healthcare settings. Although colonization is recognized as the harbinger of invasive infection, predicting which patients will develop bloodstream infection (BSI) and when this transition will occur remains a clinical challenge. In this study, patients aged ≥18 years with C. auris colonization identified at İzmir City Hospital between January 2023 and June 2025 were retrospectively analyzed. Colonization was confirmed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Of 71 colonized patients (median age 65 years; 69.0% male; 93.0% intensive care unit (ICU)-admitted), 31 (43.7%) developed bloodstream infection (BSI). In-hospital mortality was 62.0%, rising to 74.2% in the BSI group, though this difference did not reach statistical significance (p = 0.105). Competing risks analysis using the Aalen–Johansen method showed a cumulative BSI incidence of 38.2% (95% confidence interval (CI): 28–50%) by day 10 and 43.0% (95% CI: 32–54%) by day 30 following colonization detection. On multivariate logistic regression, diabetes mellitus was the sole variable independently associated with a lower risk of BSI development (adjusted odds ratio (OR): 0.19; 95% CI: 0.06–0.68; p = 0.010); this finding was directionally consistent but did not reach statistical significance in the multivariable Fine–Gray competing risks model (subdistribution hazard ratio (SHR): 0.334; 95% CI: 0.108–1.040; p = 0.057). All 40 tested isolates had high fluconazole minimum inhibitory concentration (MIC) values; micafungin susceptibility was 92.5%, while anidulafungin resistance was observed in 32.5% of isolates. Our findings demonstrate that nearly half of colonized patients developed BSI, with no identifiable safe window for intervention, underscoring the necessity of sustained infection control measures and susceptibility-guided antifungal therapy.