Increasing Fluconazole Resistance in Candida parapsilosis: A 10-Year Analysis of Blood Culture Isolates at a US Reference Laboratory (2015-2024).

Antifungal susceptibility testing among 1740 Candida parapsilosis blood isolates submitted to a United States reference laboratory (2015-2024) revealed a significant increase in fluconazole resistance from 8.2% to 20.3% (odds ratio [OR] per year, 1.13 [95% confidence interval {CI}, 1.06-1.20]; P < .001), with notable acceleration since 2021. Voriconazole resistance remained stable over this period. Micafungin resistance was rare, but intermediate susceptibility significantly increased, especially after 2021 (OR per year, 1.42 [95% CI, 1.25-1.63]; P < .001). These findings highlight important recent shifts in antifungal susceptibility among C parapsilosis isolates, emphasizing the need for ongoing surveillance and stewardship.