title: Experimental white piedra: a robust approach to ultrastructural analysis, scanning electron microscopy and etiological discoveries.
abstract: White piedra is a fungal infection characterized by nodules comprised of Trichosporon species and restricted to the extrafollicular portion of the hair shaft. The diagnosis is based on clinical and mycological characteristics, and must be confirmed with a precise identification of the etiological agent. This research aimed to develop an in vitro infection model of white piedra and analyze its morphological and ultra-structural aspects. In the process, hair infection was induced using eight isolates of the genus Trichosporon maintained in the Culture Collection Micoteca URM. The ITS and IGS1 regions were sequenced for taxonomic confirmation. Scanning Electron Microscope (SEM) was performed at the Strategic Center for Northeast Technologies (CETENE). The scanning electron microscope was equipped with an Energy Dispersion Spectrometer (EDS). The Trichosporon isolates were identified as Trichosporon asahii (6) and Trichosporon montevideense (2) by internal transcript spacer (ITS) region and intergenic spacer 1 region (IGS1) sequencing. All eight strains were used to induce the in vitro hair infection, and nodules formed after the incubation period. Temperature variations and high humidity were not observed to be related to the development of this hair disease. The main chemical constituents detected in the nodules were carbon, nitrogen and oxygen, as well as a low level of sulfur. The absence of calcium, combined with the low level of sulfur, might explain the soft nature of the white piedra nodules. This study demonstrated that several Trichosporon species may be responsible for causing white piedra.
authors.affiliation: Department of Mycology, Federal University of Pernambuco, Recife, Brazil.
authors.forename: Cicero P
authors.initials: CP
authors.lastname: Inácio
authors.affiliation: Department of Mycology, Federal University of Pernambuco, Recife, Brazil.
authors.forename: Ana Paula S
authors.initials: AP
authors.lastname: Rocha
authors.affiliation: Department of Mycology, Federal University of Pernambuco, Recife, Brazil.
authors.forename: Renan do N
authors.initials: Rdo N
authors.lastname: Barbosa
authors.affiliation: Department of Mycology, Federal University of Pernambuco, Recife, Brazil.
authors.forename: Neiva T
authors.initials: NT
authors.lastname: Oliveira
authors.affiliation: Strategic Center for Northeast Technologies, Recife, Brazil.
authors.forename: Josineide C
authors.initials: JC
authors.lastname: Silva
authors.affiliation: Department of Tropical Medicine, Federal University of Pernambuco, Recife, Brazil.
authors.forename: Reginaldo G
authors.initials: RG
authors.lastname: de Lima-Neto
authors.affiliation: Department of Pharmaceutical Sciences, Federal University of Pernambuco, Recife, Brazil.
authors.forename: Danielle Patrícia C
authors.initials: DP
authors.lastname: Macêdo
authors.affiliation: Department of Mycology, Federal University of Pernambuco, Recife, Brazil.
authors.forename: Rejane P
authors.initials: RP
authors.lastname: Neves
mesh_terms: D002118:Calcium / Q000737:chemistry; D006197:Hair / Q000648:ultrastructure; D006201:Hair Diseases / Q000382:microbiology*; D006801:Humans; D008855:Microscopy, Electron, Scanning; D009584:Nitrogen / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry; D010854:Piedra / Q000175:diagnosis* / Q000382:microbiology*; D013455:Sulfur / Q000737:chemistry; D014250:Trichosporon
chemical_list: D013455:Sulfur; D009584:Nitrogen; D010100:Oxygen; D002118:Calcium
keywords: Trichosporon sp.; energy dispersion spectrometer; experimental white piedra; scanning electron microscope