Molecular typing of Trichophyton rubrum clinical isolates from Poland

The aim of this study was to investigate the intraspecific diversity of Trichophyton rubrum clinical isolates. Thirty clinical isolates of T. rubrum were selected for molecular typing by PCR amplification of two tandemly repetitive elements (TRS-1 and TRS-2) of the rDNA and randomly amplified polymorphic DNA (RAPD) analysis with primers designated 1 and 6. The assignment to the species T. rubrum was achieved by nested PCR of ITS1. Five PCR types were produced from the TRS-1 and three from the TRS-2 locus. Thirteen and 23 individual profiles were obtained by RAPD, with primer 1 and 6 respectively. At the phylogenetic level, 26 (87%) isolates were allocated into four clusters, with each cluster comprising isolates of over 80% similarity. The reproducibility of TRS typing was 100%, whereas that of RAPD was 40% and 30%, when using primer 1 and 6 respectively. Neither correlation between the morphological characteristics and the TRS-1-TRS-2 or RAPD genotype nor between TRS-1-TRS-2 and RAPD genotyping was observed. Although both the TRS amplification and RAPD analysis possess the ability to discriminate between T. rubrum strains, the TRS typing method is particularly valuable as its results are much more reproducible, more easily interpreted and recorded than those generated by RAPD.