Standardization of a hyphal inoculum of aspergilli for amphotericin B susceptibility testing

Standardized, evenly dispersed hyphal suspensions served as the inoculum in a microtiter technique for amphotericin B antifungal susceptibility testing. Preliminary testing with six strains of Aspergillus fumigatus and A. flavus produced consistent and reproducible results at 30 degrees C over 24 h. The observed amphotericin B MICs required for hyphae (0.3 to 0.6 microgram/ml) were comparable to MICs required for conidia (0.16 to 0.6 microgram/ml). The results were evaluated and compared with previously published information.