Sporothrix schenckii Complex: Genetic Polymorphism

Abstract

Sporothrix schenckii is an ascomycetous dimorphic fungus that, for over a century, was recognized as the sole agent of sporotrichosis, a subcutaneous mycosis with a worldwide distribution. Based on physiologic and molecular aspects, however, it has been proposed that S. schenckii is a complex of distinct species: S. brasiliensis, S. mexicana, S. globosa, S. schenckii sensu stricto, S. luriei, and S. pallida (formerly S. albicans). Before the description of these species, several authors had pointed to a high level of genetic diversity among Sporothrix spp. strains according to geographic distribution and clinical forms. Phenotypic characterization is usually made through morphology of colony and conidia and biochemical profiles. However, the correlation between molecular data and phenotypic characteristics is fundamental to the identification of the Sporothrix complex. Molecular information about the Sporothrix species complex is scarce. Until now, S. brasiliensis and S. schenckii s. str. are the only clinically relevant species of this complex with an elucidated genome sequence, thus limiting molecular knowledge about the cryptic species of this complex, the population structure, and the sexual form of all S. schenckii complex species. In this chapter, we focus on the current molecular tools applied to the identification of the Sporothrix complex species and on published studies on Sporothrix spp. sexuality, and we outline the geographic distribution of Sporothrix complex species.