Assignment and serotyping of Trichosporon species: the causative agents of summer-type hypersensitivity pneumonitis.

We re-valued three antigenic types within the genus Trichosporon as the causative agents of summer-type hypersensitivity pneumonitis (SHP). Corresponding standard strains, TIMM 1573 (serotype I), TIMM 1318 (serotype II), and M9456 (serotype III) were assigned to species T. mucoides, T. asahii and T. montevideense, respectively, based on 95% or more DNA/DNA relatedness with each type of culture and other genetical, physiological and morphological characteristics. To confirm the significance of these serotypes, 98 other strains of Trichosporon isolated from patients' environments and 24 CBS strains, including type cultures of species described within the genus, were serotyped. Serum antibody analysis of 220 SHP patients against Trichosporon spp. were also examined to estimate the antigenic profile of SHP. The present results indicate that T. asahii and T. mucoides, which are the most common causes of trichosporonosis, appear to be the major causative agents of SHP. These observations suggest a common pathogenesis of Trichosporon inducing hypersensitivity and infection, depending on the immunological status of the host.