Comparison of Tablet and Disk Diffusion Methods for Fluconazole and Voriconazole In Vitro Activity Testing Against Clinical Yeast Isolates

Abstract

We have compared a commercially available tablet diffusion method for the In Vitro antifungal susceptibility testing of fluconazole (FCZ) and voriconazole (VCZ) with the disk diffusion method M44 (CLSI) with 282 clinical yeast isolates. The superior stability of antifungal agents in tablets can explain the differences for each category of susceptibility by both methods.

Neo-Sensitabs™ tablets antifungal susceptibility testing showed an excellent correlation (0.98 for FCZ and 0.98 for VCZ at 24h and 0.96 for FCZ and 0.94 for VCZ at 48h), a reduced percentage of disagreements (4.6% and 8.2% for FCZ at 24h and 48h respectively; 1.1% and 2.1% for VCZ at 24h and 48h respectively) and the absence of statistically significant difference in comparison with the reference protocol for performing antifungal susceptibility testing with the agar diffusion method.

Keywords:

• Neo-Sensitabs™ tablets
• M44-A
• antifungal susceptibility
• disk diffusion
• Candida