What type of stain would you use to identify fungus in tissue samples?

Gomori's methenamine silver (GMS) stain is specifically designed for identifying fungal organisms within tissue samples. It utilizes a silver-based dye that binds to the polysaccharides present in the cell walls of fungi, making it invaluable for visualizing various fungal structures under a microscope. The GMS stain highlights the unique morphology of fungi, including hyphae and spores, which can be critical for diagnostics.

In contrast, hematoxylin and eosin stain is a general staining method used to evaluate tissue morphology, but it does not specifically target fungal elements, making it less useful for this purpose. The Diff-Quik stain is primarily used for rapid cytological preparations and is not suitable for identifying fungal infections in tissue specimens. The periodic acid-Schiff (PAS) stain is also a useful stain for fungi, as it highlights carbohydrate-rich components, but it is not as specific as GMS for fungal identification. Thus, GMS stands out as the most effective choice for identifying fungi in tissue samples.