Differentiation of Trichophyton rubrum clinical isolates from Japanese and Chinese patients by randomly amplified polymorphic DNA and DNA sequence analysis of the non-transcribed spacer region of the rRNA gene.

ABSTRACT

BACKGROUND: Trichophyton rubrum is the most common pathogen causing dermatophytosis worldwide. Recent genetic investigations showed that the microorganism originated in Africa and then spread to Europe and North America via Asia. OBJECTS We investigated the intraspecific diversity of T. rubrum isolated from two closely located Asian countries, Japan and China. METHODS: A total of 150 clinical isolates of T. rubrum obtained from Japanese and Chinese patients were analyzed by randomly amplified polymorphic DNA (RAPD) and DNA sequence analysis of the non-transcribed spacer (NTS) region in the rRNA gene. RESULTS: RAPD analysis divided the 150 strains into two major clusters, A and B. Of the Japanese isolates, 30% belonged to cluster A and 70% belonged to cluster B, whereas 91% of the Chinese isolates were in cluster A. The NTS region of the rRNA gene was divided into four major groups (I-IV) based on DNA sequencing. The majority of Japanese isolates were type IV (51%), and the majority of Chinese isolates were type III (75%). CONCLUSIONS: These results suggest that although Japan and China are neighboring countries, the origins of T. rubrum isolates from these countries may not be identical. These findings provide information useful for tracing the global transmission routes of T. rubrum.