First isolation of Trichophyton raubitschekii (syn. T. rubrum) in Europe

Trichophyton raubitschekii is a rare dermatophyte which belongs to the Trichophyton rubrum species complex. Since 1981, only a few cases of dermatophytosis due to this anthropophilic causative agent were published. In this paper the authors report the first cases of Tinea corporis caused by Trichophyton raubitschekii (syn. T. rubrum) in Europe. The patients, one immigrant from Ghana and three from Cameroon, had typical lesions of tinea corporis. Four strains were isolated and characterized by conventional and molecular methods. On morphological and physiological grounds the isolates were identified as T. raubitschekii by the following phenotypical features: (1) velvety colony texture; (2) brown pigment; (3) abundant macroconidia and (4) positive urease activity. Molecular diagnostics were performed by single strand conformation polymorphism (SSCP) and sequence analysis of the ATPase9 intron of the mitochondrial (mt) DNA and the internal transcribed spacer (ITS) region of the rDNA, respectively. The ITS sequences and SSCP patterns of the ATPase9 intron were found to be identical among the four strains and also when compared to reference strains of T. rubrum. As shown in the present paper, T. raubitschekii is genetically identical to T. rubrum but differs in some phenotypical characteristics. Since misidentification with other dark-coloured dermatophyte variants is possible, medical mycologists should bear in mind the special morphological characteristics of T. raubitschekii (syn. T. rubrum) for future identifications.