Persistent Non-albicans Predominance, High Mortality, and Azole-Non-Susceptible Candida tropicalis: A 15-Year Pediatric Invasive Candidiasis Cohort in Southern Thailand.

Invasive candidiasis (IC) causes substantial mortality in critically ill children, yet pediatric data from Southeast Asia remain limited. We retrospectively studied 117 children aged ≤ 18 years with proven IC at a Thai tertiary center (2009-2023). Thirty-day mortality was 25.6%, rising to 47.1% in neonates; death occurred a median of 5.5 days after diagnosis. Firth penalized logistic regression identified septic shock (aOR, 4.89; 95% CI, 1.77-14.88) and thrombocytopenia (aOR, 3.74; 95% CI, 1.17-15.35) as independent mortality predictors, with septic shock remaining significant across all analytical frameworks, including Fine-Gray competing-risks analysis. Apparent mortality associated with absence of antifungal therapy reflected reverse causation: in all six untreated children who died, Candida was reported only 2-7 days after death. Candida albicans (43.6%), C. tropicalis (30.8%), and C. parapsilosis (24.8%) predominated; C. glabrata was absent. Non-albicans Candida was already common at the outset and showed no statistically detectable increase over 15 years. Among 45 consecutive pediatric bloodstream isolates (2021-2026), amphotericin B and echinocandins largely retained activity, whereas reduced azole susceptibility was concentrated in C. tropicalis (47.8% fluconazole-susceptible; 26.1% posaconazole wild-type). The reduced azole susceptibility of local C. tropicalis isolates argues for periodic reassessment of institutional susceptibility data rather than reliance on historical or external epidemiology; in comparable settings, an echinocandin or amphotericin B is a more reliable empiric choice than an azole, pending species identification and susceptibility results.