In vitro activity of fluconazole and voriconazole against isolates of Candida albicans from patients with haematological malignancies.

We evaluated the activity of fluconazole and voriconazole against 83 Candida albicans isolates from patients with haematological malignancies, comparing the NCCLS microdilution method (M27-A) with a modified method with RPMI-2% glucose and MIC endpoint at 50% inhibition. Both drugs were highly active regardless of the year, the site of isolation of the strain and the test method employed. In several strains isolated during the last few years, trailing growth leading to difficulty in interpretation of the endpoint of the test has been observed for both drugs by the NCCLS method, but not by the modified method. In our experience, azole resistance of C. albicans is still not a clinical problem, however, the emerging phenomenon of the 'trailing effect' by the NCCLS method, even though resolvable by technical modifications, seems at least to indicate a reduction in the inhibitory activity of the azoles.