Molecular identification and strain typing of dermatophyte fungi

The rDNA spacer regions provide easily accessible, polymorphic genetic loci for both species and strain identification of dermatophyte fungi. Nucleotide substitutions and length polymorphisms in the internal transcribed spacers (ITS) can be indexed by sequencing or by PCR restriction endonuclease analysis, and provide a rapid and accurate means of identifying dermatophyte taxa. Multiple sets of tandem repeats that vary in copy number both within and between strains produce length heterogeneity in the nontranscribed spacer (NTS) region. Amplification of these repeats using specific PCR, or their detection by Southern hybridisation with a generic ribosomal DNA probe, provides a sensitive and discriminatory technique for strain identification in T. rubrum and other dermatophyte fungi.