The fungus has also gone by the names of Phaeoannellomyces werneckii, Exophiala werneckii,and Cladosporium werneckii. This fungus is found in the soil, sewage, and decomposing vegetation of tropical or subtropical coastal regions. In particular, these areas include the Caribbean and the coast of South America. The fungus causes painless brown or black patches to grow on palms and feet. Sometimes other areas of the body, such as the neck and trunk, can be affected. What causes it?
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Badali ,3,4,5 G. Cruz ,2 J. Araiza ,1 M. Cruz ,2 L. Fierro ,2 and R. Ponce 2 A. CP , Mexico Find articles by A. Bonifaz H. Badali G. CP , Mexico Find articles by M. Cruz J. CP , Mexico Find articles by J. Araiza M. Cruz L. CP , Mexico Find articles by L. Fierro R. Any of the above conditions can be waived if you get permission from the copyright holder.
This article has been cited by other articles in PMC. Abstract Tinea nigra is a superficial mycosis caused by Hortaea werneckii. It is an infrequent asymptomatic infection that affects human palms and soles, and is mostly observed in tropical countries. We evaluate retrospectively twenty-two confirmed cases of tinea nigra from a total of eleven yr — and discuss the epidemiology, clinical features and treatment of this disease.
In twelve cases, adults were involved, in 10, children. In nineteen cases the disorder was located on palms of hands and in three on soles of feet. In all cases, the obtained isolates were morphologically identified as Hortaea werneckii and the identification of ten isolates was retrospectively confirmed with the help of sequences of the internal transcribed spacer regions of the ribosomal DNA.
The patients received topical treatment with Whitfield ointment, ketoconazole, bifonazole, or terbinafine. Treatment with keratolytic agents and topical antifungals was effective. It is an infrequent, asymptomatic infection, limited to tropical and subtropical countries. Most typically, it affects palms of hands but is occasionally found on other parts of the body.
Symptoms include hyperchromic plaques, in which the fungus may or may not live in commensalism with other organisms Hughes et al. The disorder has longtime been regarded as an infection and therefore Hortaea werneckii was classified as a BioSafety Level 2 organism Anon No keratinolysis can be observed and the adhesion to human hands is to be explained by the hydrophobic character of the yeast cells.
It has been proven that the natural habitat of the fungus comprises hypersaline environments due to its halophilic behaviour Zalar et al. The present article is a retrospective report of cases of tinea nigra, its epidemiological, clinical, and therapeutic features, as well as a review of the disorder.
Each of the strains was identified using macro- and microscopical features. The identification of ten strains was verified with sequences of the internal transcriber spacer regions ITS of the rDNA.
Methods for DNA extraction and sequencing were those of Badali et al. Sequences were compared using a black yeast molecular database maintained at the Centraalbureau voor Schimmelcultures, Utrecht, The Netherlands. Table 1. Demographic data of 22 patients with tinea nigra. Case nr.
What Is Tinea Nigra?
Genus: Hortaea Description and Natural Habitats Hortaea werneckii is a dematiaceous yeast that inhabits the soil, particularly in tropical and subtropical climates. It is halophilic and has also been isolated from saltwater fish. Hortaea werneckii is an occasional cause of human infections [ ]. Species Hortaea werneckii is the only species classified in the genus Hortaea. This particular fungus has previously been classified in various other genera and the genus Hortaea appears as its most currently accepted classification. See the list of obsolete names and synonyms for older names of Hortaea werneckii. Pathogenicity and Clinical Significance Hortaea werneckii is the causative agent of Tinea nigra.
Short descriptions and photographs of some photogenic microorganisms. Pathogenicity: H. This infection usually manifests itself as brown to black macules which are most often found on the palms of the hands. The appearance may initially resemble that of malignant melanoma.