ABSTRACT
Since 1956 and until the introduction of fluconazole in 1990, amphotericin B was the only available antifungal agent for the treatment of severe fungal infections; consequently, there was little need for routine susceptibility testing. Furthermore, the emergence of the AIDS pandemic, modern patient management technologies and therapies such as bone marrow and solid-organ transplants, and the more aggressive use of chemotherapy have resulted in a rapidly expanding number of patients highly susceptible to mycotic infections. With the increased incidence of fungal infections and the parallel development of resistance to established agents, the laboratory’s role in the selection of antifungal therapy has gained greater attention. The Clinical and Laboratory Standards Institute (CLSI, formerly NCCLS) has approved standard broth dilution methodologies for susceptibility testing of
Candida
spp. and
Cryptococcus neoformans
to
amphotericin B, flucytosine, ketoconazole, fluconazole, itraconazole, voriconazole, and posaconazole [1]. The CLSI antifungal susceptibility testing assays (broth dilution and disk diffusion) and two commercial methods for yeasts are described in this chapter. The endpoints determined by these methods are the minimum inhibitory concentration or the MIC and the inhibition zone diameter (disk testing).
