First report of white piedra caused by Cutaneotrichosporon debeurmannianum

Abstract

Piedras are small nodules found on the hair shafts. White piedra was initially described as caused by Trichosporon beigelii, which was later reclassified in several species. We describe the first case of white piedra caused by Cutaneotrichosporon debeurmannianum. Affected hairs were examined in natura with scanning electron microscopy, after gold metallization. The typical whitish cerebriform creamy colony was obtained in Sabouraud medium. Fungal genomic DNA extracted from cultures and locus was amplified with the NL1/NL4 primer pair from the D1/D2 region of the large ribosomal subunit (LSU) of 28S rRNA. With scanning electron microscopy, nodules are easily identified surrounding the hair shaft; with high magnifications, rounded structures adhered to each other were identified. Comparison of the nucleotide sequences of IMT-1703 Cutaneotrichosporon debeurmannianum revealed 99.6% similarity with the 28S large ribosomal unit rDNA sequence. This case of white piedra was caused by Cutaneotrichosporon debeurmannianum.

Figure 1. (a) whitish cerebriform creamy fungal colony; (b) microsocopic aspect with predominance of blastoconidia; (c) scanning electron microscopy, low magnification with a nodule surrounding the hair shaft (× 400); (d) scanning electron microscopy, high magnification, detailing the fungal structures (× 7,500).

Figure 2. Agarose gel electrophoresis (Invitrogen, USA) at 2% showing the amplification products of isolates IMT1703 (600bp), positive controls (C+, IMT38), and negative control (C-) with primers NL1 and NL4 (Kurtzman, C. P., and C. J. Robnett. 1997). M = Molecular weight marker (Invitrogen, USA).

Figure 3. Phylogenetic tree of isolate IMT1703 from the D1/D2 region of LSU, obtained by the maximum likelihood (ML) with 1000 bootstrap replications. The accession numbers of the strains Genbank are indicated on the taxon labels. Trichosporon asteroides and T. asahii are the outgroup. Sequence analysis obtained after amplification of the DI/D2 region of LSU showed 100% identity with the Genbank reference strain under the access Nº KY107315.1.