Genotyping of Paracoccidioides brasiliensis directly from paraffin embedded tissue

Abstract

Based on polymorphisms of the gp43 precursor gene, genotyping of Paracoccidioides brasiliensis was achieved in 6 out of 10 paraffin-embedded tissue samples by modifying a nested PCR procedure used in the diagnosis of the fungal infection. Nine of the samples originated in Brazil. Three sequences were identical to a previously published consensus sequence identifying the P. brasiliensis isolates as members of the formerly named species 1. In contrast, two sequences revealed substitutions identical to isolates of the phylogenetic species 2. Applying the method to a lung biopsy from a proven case of paracoccidioidomycosis diagnosed in Austria, the gp43 sequence revealed substitutions so far only described in five strains originating from Venezuela. Combining travel history and result of this new method, the most probable country of origin of the infections could be identified. Since endemic mycosis are often diagnosed by histopathology only, our method could help to extend epidemiological studies of paracoccidioidomycosis.