In situ hybridization in paracoccidioidomycosis.

In situ hybridization (ISH) was performed using oral biopsies from patients with paracoccidioidomycosis and guinea pig testes inoculated with a culture of Paracoccidioides brasiliensis isolated from soil, employing both a 14 base-pair specific oligoprobe (ACT CCC CCG TGG TC) and its complementary sequence. When combining ISH with the Gridley stain which detects fungal cell walls, about 2-3% of the fungal cells present in the tissues were labelled. When the complementary probe was used, labelling was higher, reaching the 3% level.