IN-VITRO SUSCEPTIBILITY OF CANDIDA SPECIES ISOLATED FROM PATIENTS WITH HEMATOLOGICAL MALIGNANCIES

Candida spp. (83 isolates including C. (Torulopsis) glabrata) were tes ted in vitro for their susceptibility to 5-fluorocytosine, amphoterici n B, ketoconazole, itraconazole, fluconazole, and miconazole. The yeas ts were isolated from clinical specimens, mostly from the lower respir atory tract, of 30 oncologic patients, 27/30 with haematological malig nancies, during a 6-month period (December 1991-May 1992). Minimal inh ibitory concentration (MIC) and minimal fungicidal concentration (MFC) values of the 6 drugs were obtained for each yeast using a microdilut ion broth method developed in our laboratory. Amphotericin B, and 5-fl uorocytosine were active against the majority of the yeasts with MIC90 /MFC90 values within achievable serum concentrations (3.12/6.25 mu g m l(-1) and 0.625/0.625 mu g ml(-1) respectively). Azole derivatives sho wed a species-specific activity. MFC values were two to four times hig her than those of the MICs, confirming the fungistatic rather than fun gicidal activity of azole derivatives. An interesting correlation was found when the in vitro susceptibility values of the isolates were com pared with data of patients with or without antifungal prophylaxis or therapy during that period. In general, with respect to fluconazole, C . albicans strains isolated from patients who received no treatment sh owed MIC and MFC values lower than those obtained from patients who we re under prophylaxis or treatment with this drug. Fluconazole administ ration appears to influence in vitro susceptibility testing.