Susceptibility Testing of Candida auris Isolates

Abstract

Susceptibility testing of isolates of Candida auris is helpful as a guide to the selection of the most appropriate antifungal agent for treatment as different clades and strains within clades often demonstrate markedly different susceptibility profiles. Some strains are relatively susceptible to all antifungal drugs, but most demonstrate innate resistance to fluconazole, many are cross-resistant to other azoles and others demonstrate resistance to other classes of antifungal. The finding of multi-drug resistance, where an isolate is resistant to two or more classes of antifungal agent, is not uncommon, and development of resistance during a course of treatment has also been documented. This chapter describes a reference broth microdilution method for susceptibility testing and a commercially available gradient strip method.