Analyse critique des tests de sensibilité in vitro aux antifongiques

[Susceptibility testing of fluconazole: evaluation of a multicenter study of the working group "Clinical Mycology" of the German Speaking Mycological Society]

In a collaborative study for in vitro testing of fluconazole against clinical yeast isolates participated 21 laboratories of the working group "Clinical Mycology" of the German Speaking Mycological Society. In these centers, according to a standard test protocol 1181 clinical isolates from 1033 patients were tested to their susceptibility against fluconazole by microdilution, agar diffusion and partly by agar dilution. Approximately 600 strains (59.1%) of the collective of 1106 isolates sent to a reference center underwent retesting in one laboratory (center 13). These strains demonstrated almost the same species distribution as the total collective. For 80% of all isolates a MIC of < or = 4 micrograms/ml and for 90% of the Candida albicans strains a MIC of < or = 2 micrograms/ml has been determined. Only approx, 9% of all isolates (4% with Candida albicans) showed a MIC of < or = 25 micrograms/ml. By parallel testing of 10 control strains issued by the reference center to the laboratories, the inter- and intra-laboratory comparability of the susceptibility testing of fluconazole was checked. The results demonstrated that under appropriate technical prerequisites and standardised test conditions, the methods used routinely in bacteriology microdilution, agar dilution and agar diffusion may also be applied in a reproducible way in the routine mycological laboratory for the susceptibility testing of yeasts.