Objectives
Fluconazole non-susceptibility (FNS) rates have increased among C. tropicalis isolates in Asia. We aimed to explore the proportions and risk factors of candidemia caused by FNS C. tropicalis and the impact of FNS on patient outcomes.
Methods
There was a prospective Candida bloodstream infections (BSIs) cohort in a single medical center at Northern Taiwan. We retrospectively analyzed the first episode of C. tropicalis BSIs between 2011 and 2017. Antifungal susceptibility testing of the first isolate of each episode was performed by the microdilution colorimetric Sensititre YeastOne SYO-09 panel, and the results were interpreted according to Clinical and Laboratory Standards Institute (CLSI) species-specific breakpoints.
Results
During the study period, three hundred and forty-four episodes of C. tropicalis BSIs were identified. Of them, 58 (16.9%) first blood isolates were non-susceptible to fluconazole, including 10 isolates belonging to susceptible dose-dependent and 48 isolates belonging to resistance. The proportions of C. tropicalis BSIs and fluconazole resistant rates showed an increasing trend by years (both P = 0.07, Figure 1). There were no differences of patient outcomes, including 14-day and 30-day mortality, and persistence, between FNS BSIs and fluconazole susceptible (FS) BSIs (Figure 2). Compared to patients with FS BSIs, those with FNS BSIs were more likely to have moderate to severe liver disease, leukemia, receipt of steroid and antifungal exposure (AE), but less receipt of parental hyperalimentation compared to those infected by FS isolate (all P < 0.05). Of note, around 55% patients with FNS BSIs were azole naïve (Table 1).
Conclusion
Fluconazole resistance increased in C. tropicalis BSIs, but didn’t worsen patient outcomes. Immunocompromised hosts and those with azole exposure were at risk for FNS C. tropicalis BSIs. Further investigations were warranted for azole naïve patients with FNS C. tropicalis BSIs.

Risk factors and clinical outcomes of patients with fluconazole nonsusceptible Candida tropicalis bloodstream infections