PCR Typing of Trichophyton Rubrum Isolates by Specific Amplification of Subrepeat Elements in Ribosomal DNA Nontranscribed Spacer

Background: Trichophyton rubrum (T. rubrum) is the most common cause of dermatophytosis of skin and nail tissue. Strain identification in Trichophyton rubrum is important for identification of strain-related differences in infectivity potential or transmissibility and epidemiological studies. PCR typing could determine whether the original isolate is responsible for re¬infection or a new strain has been acquired.Methods: A minipreparation method for DNA from dermatophytes was used. Tandemly repetitive subelements (TRS-1 & TRS-2) of NTS region at ribosomal DNA of 23 T.rubrum isolates were amplified and the PCR products were separated by electrophoresis in 2% agarose gel (200 mA, 140 V), visualized by staining with ethidium bromide, and photographed.Results: On the basis of copy number of TRS-1 and TRS-2, 8 out of our 23 samples were type 2 & II, respectively. Six of them were type 3 & II, four isolates were type 1 & II, two isolates were type 4 & II, two isolates were type 1 & I and one isolate was type 5 & II.Conclusion: In this study, most of T. rubrum isolates were type 2 & II, dissimilar to European studies where type 1 & II has been the most common. The present study showed that 26.1% of Iranian isolates were type 1 in contrast with a previous study which has demonstrated a much lower prevalence in Asians (5%).