Standardized susceptibility testing of fluconazole: an international collaborative study
M A Pfaller1, B Dupont, G S Kobayashi
1Department of Pathology, Oregon Health Sciences University, Portland 97201.
Antimicrobial Agents and Chemotherapy
|September 1, 1992
Summary
This study evaluated fluconazole susceptibility testing methods. Broth dilution showed excellent reproducibility and acceptable interlaboratory agreement, while disk diffusion had good reproducibility but poor interlaboratory agreement.
Area of Science:
- Medical Microbiology
- Antifungal Drug Susceptibility Testing
Background:
- Accurate antifungal susceptibility testing is crucial for guiding treatment decisions.
- Standardization of testing methods for fluconazole is essential for reliable clinical interpretation.
Purpose of the Study:
- To assess the reproducibility and agreement of broth dilution (MIC) and disk diffusion methods for fluconazole susceptibility testing.
- To compare the performance of these methods across multiple reference laboratories.
Main Methods:
- An international collaborative study involving eight reference laboratories.
- Testing of ten yeast isolates using broth dilution and disk diffusion methods.
- Utilized a chemically defined medium (High-Resolution Antifungal Assay Medium).
Main Results:
- Broth dilution demonstrated excellent intralaboratory reproducibility (95.7%) and acceptable interlaboratory agreement (84%).
- Disk diffusion showed good intralaboratory reproducibility (91%) but poor interlaboratory agreement (59%).
- Rank order agreement with reference was comparable for both methods (median 80%).
Conclusions:
- Broth dilution appears more reliable for interlaboratory standardization of fluconazole susceptibility testing.
- Further development is needed to improve the interlaboratory consistency of disk diffusion methods.
- These findings support the ongoing efforts to standardize antifungal susceptibility testing.
