ABSTRACT
Antifungal resistance is a significant problem in hospitalized patients, and a major cause of morbidity and mortality. More recently, resistance has also been reported for the newer antifungal agents like echinocandins, underscoring the importance of gaining insight into the mechanisms of antifungal resistance. In this chapter we will summarize the methods used to evaluate antifungal resistance, based on determination of minimum inhibitory concentration (MIC, using microdilution method, disk diffusion assay, Epsilometer Strip test), minimum effective concentration (MEC), and time-kill assays. We will also review the incidence of resistance against commonly used antifungal agents among yeast and filamentous fungi. The last section of the chapter outlines the mechanisms employed by fungi to avoid the action of antifungal agents (including modulation of drug efflux pumps, membrane sterols, cell wall polysaccharides, like β-glucan and biofilm formation).
