[Fluorescence microscopy detection of mycopathogens using Rylux BSU]

Rylux BSU (Synthesia, Pardubice--Semtín), a derivative of diaminostilbendisulphonic acid, has a good affinity to chitin of fungal cell walls as well as to cellulose of algae. A histologic method using this compound for detection of fungi in dermatology is presented accompanied with results of a quick diagnostic procedure. Pathogenic fungi were stained with a 2 per cent solution of Rylux BSU in phosphate buffer (pH 7.3) or in a 2 per cent aqueous solution of NaOH with an admixture of 10 per cent dimethylsulphoxide. A yellow green fluorescence of the cell walls of fungi (tested on 52 species) and algae (2 species) was evoked by incident blue light (max. filter transmission for 405 nm) combined with a barrier filter (max. 578 nm). Fluorescence was not fading and remained stable in Canada balsam. Moreover, the method could be applied on sections previously stained (HE, Weigert, Giemsa, KOH-preparations) because of more information offered by a combined procedure.