Development of an oligonucleotide probe specific for Trichophyton rubrum

A species-specific DNA probe was developed to detect the dermatophyte speci es Trichophyton rubrum. The selected oligonucleotide sequence is derived fr om the highly variable internal transcribed spacer 2 region of the ribosoma l DNA operon, The specificity of the non-radioactive labelled oligonucleoti de probe was tested against related dermatophytes, other eukaryotic microor ganisms and against human DNA, No cross-hybridization was found, and hybrid ization signals were invariably detected in all T. rubrum strains investiga ted. In addition, no homologous sequences were found searching the EMBL dat abase. Experiments to establish a method for isolating DNA directly from cl inical specimens gave successful amplification and hybridization products i n about 30% of the samples.