Microscopic Detection of Yeasts Using Fluorescence In Situ Hybridization

Fluorescence in situ hybridization (FISH) has been widely used for the detection and identification of microorganisms in their natural environments. In this chapter we describe the use of a simple FISH-based protocol to detect and identify clinically relevant yeast species in culture and biological samples using Cryptococcus neoformans as a model. After fixation of cells with paraformaldehyde, the same are embedded in hybridization buffer containing specific fluorochrome-labeled oligonucleotide probes. After incubation and a subsequent washing step for removing unbound probes, samples are analyzed by epifluorescence microscopy.