Due to Increasing the frequency of isolates resistant to antifungals, therapy requires reliable and easy to use susceptibility testing systems. Tea Recently Developed ATB ® FUNGUS 2 strip is a broth micro-dilution method dedicated to measure the in vitro susceptibility by MIC determination of Candida species and Cryptococcus neoformans to major antifungal drugs: 5-Flucytosine (5FC) Amphotericin B (AMB), Fluconazole (FCA ) and itraconazole (ITR). A comparison study with the NCCLS reference method M27-A Was Made to evaluate-the performance of the system.
A total of 100 collection isolates of Candida species and C. neoformans Were tested. Two Quality Control strains Were added. A reproducibility kit Composed of 8 strains Was tested 5 times at two different laboratories. ATB MICs (visual and automated readings) Were therefor obtained after-24 hours (or 48 hours in Some boxes if no OCCURS growth at 24 h) for Candida species and 48 after-hours for C. neoformans . For Each Each drug and reading mode, the essential agreements entre Both methods (percentage agreements within 2 log 2 dilutions of the reference MIC) and ATB FUNGUS 2 reproducibility (percentage agreement Within 1 log 2 dilution) Were Assessed.
A total of 800 MIC values (400 For Each reading mode) Were analysed. The overall essential agreements Were 94% and 99% for the automated (Aut) and visual (Vis) readings, respectivement. The essential agreements by drugs Were (Aut / Vis): 5FC, 97% / 100%; AMB 97% / 100%; FCA, 93% / 97%; ITR, 89% / 98%. No significant bias was found. The ATB FUNGUS 2 inter-laboratory reproducibility Was > 99% whatever the reading is fashion and the QC strain MICs Were always in the expected ranges.
Selon this study, the ATB ® FUNGUS 2 system allows simple, objective, reproducible and accurate determination of MICs for the four antifungal drugs. Consequently, this new standardized reagent is a valuable alternative to the NCCLS reference method for routine susceptibility testing of yeasts.
Full conference title:
- RICAI 24th (2004)