Development of molecular methods for identification of Schizophyllum commune from clinical samples

In the last 50 years, to our knowledge, only 16 cases of diseases caused by Schizophyllum commune in humans have been reported. Within only 6 months, we found four isolates of this basidiomycetous fungus, obtained from patien ts suffering from chronic sinusitis. The cultures of the isolated fungi sho wed neither clamp connections nor fruiting bodies (basidiocarps), which are distinctive features for S. commune, but fast-growing cottony white myceli um only, This was harvested, and DNA was extracted. The internal transcribe d spacer region of the ribosomal DNA (rDNA) was amplified with fungus-speci fic primers, and the PCR products were sequenced. Two strains of S. commune , collected from branches of a European hornbeam (Carpinus betulus) and a t ree of heaven (Ailanthus altissima), respectively; four specimens from the herbarium of the Institute of Botany, Karl-Franzens-University Graz; and tw o strains from internationally known culture collections (CBS 340.81 [ATCC 44201] and CBS 405.96) were investigated in the same way. The sequence data of all strains were compared and showed homology of over 99% in this 660-b p-long fragment of rDNA. With these results, a map of restriction enzyme cu tting sites and a primer set specific for S. commune were created for relia ble identification of this human pathogenic fungus.