White piedra and Trichosporon species in equatorial Africa. I. History and clinical aspects: an analysis of 449 superficial inguinal specimens

Abstract

Summary. White piedra is a hair infection characterized by nodules composed of fungal elements which envelop the hair shaft. Classically, this infection was considered to be produced by an asexual yeast‐like fungus, Trichosporon beigelii. At present, in accordance with studies carried out previously, this species is subdivided into six newly defined distinct species (T. asshu, T. ovoides, T. inkin, T. mucoides, T. asteroides and T. cutaneum), all belonging to the class Basidiomycetes. Although widespread, white piedra has not previously been described in tropical regions of Africa. The present study, carried out in Libreville (Gabon), an equatorial region of Africa, shows that the incidence of this infection is quite high (18% of 449. inguinal specimens) in the female population aged 15–60 years, with a predominance in young patients (15–44 years). The relationship between the clinical manifestations and the specific hair lesions is also detailed. Three species belonging to the genus Trichosporon were identified: T. mucoides, T. asahii and T. inkin. Zusammenfassung. Die weiße Piedra ist eine Haarinfektion, charakterisiert durch harte Knötchen, die aus Pilzelementen bestehen und den Haarschaft umgeben. In der klassischen Definition wurde diese Infektion als durch Trichosporon beigelii verursacht angesehen, einem asexuellen, hefeähnlichen Pilz. In Übereinstimmung mit neueren Untersuchungen wird diese Art jetzt in sechs selbständige Arten unterteilt: T. asahii, T. ovoides. T. inkin, T. mucoides, T. asteroides and T. cutaneum, die alle zur Klasse der Basidiomyzeten gerechnet werden. Obgleich weit verbreitet, wurde die weißie Piedra niemals in den tropischen Gebieten Afrikas beschrieben. Die vorliegende Studie, durchgeführt in Libreville (Gabun), einer äquatorialafrikanischen Region, zeigt, daß die Häufigkeit dieser Infektion ganz beträchtlich ist, nämlich bei 18% von 449 Untersuchungsproben der Inguinalregion in der weiblichen, zwischen 15 und 60 Jahre alten Bevölkerung, vorherrschend bei jüngeren Patientinnen im Alter von 15–44 Jahren. Die klinischen Manifestationen und die spezifischen Haarbefunde werden im Einzelnen dargestellt. Es wurden drei Arten der Gattung Trichosporon gefunden: T. mucoides, T. asahii, T. inkin.

Onychomycosis caused by Trichosporon mucoides

“…Three species were recognized: T. mucoides (25 strains), T. inkin (20 strains), and T. asahii (seven strains). 6,7 The identity of these strains was confirmed by means of an agglutination method performed with monospecific antisera. This method allowed the verification of the presence of antigens common to the genera Cryptococcus and Trichosporon.…”

“…In the 1990s, it was observed that T. mucoides was sometimes responsible for white piedra. 5,6 Previously, white piedra was considered to be caused by Trichosporon beigelii. Subsequently, this species was divided into six distinct species: Trichosporon asahii, Trichosporon asteroides, Trichosporon cutaneum, Trichosporon inkin, T. mucoides, and Trichosporon ovoides.…”

Morphological and biochemical characterization of the aetiological agents of white piedra

“…is known worldwide as white piedra and is considered a sporadic infection that occurs in tropical and temperate climates (Fishman et al 1980, Thérizol-Ferly et al 1994, Elmer et al 2002, Youker et al 2003, Ghorpade 2004, Kiken et al 2006, mostly in rainy periods (Kamalam et al 1981).…”

“…White piedra, a mycosis that occurs in some animals, such as horses, monkeys and domestic animals, as well as humans (Kaplan 1959), is found within a wide geographical distribution, including tropical and temperate regions, occurring mainly in South America, Africa, Europe and Asia (Kamalam et al 1981, Thérizol-Ferly et al 1994, Ghorpade 2004, Schwartz 2004). There are also some cases in the USA (Elmer et al 2002, Youker et al 2003, Kiken et al 2006 and it has been found to be endemic to Texas (Kalter et al 1986).…”

White piedra and Trichosporon species in equatorial Africa. III. Identification of Trichosporon species by slide agglutination test

“…In dermatological and fungal study recently carried out in Libreville (Gabon) we were able to distinguish 52 Trichosporon strains isolated from female patients from this humid tropical region [7,8]. Since we have long been interested in the identification of yeast species by slide agglutination tests [9] we tried, in the present study, to assess the applicability of these methods in the identification of Trichosporon species according to the new classification of GuCho et al [4,5].…”