AN ATYPICAL ISOLATE OF PARACOCCIDIOIDES-BRASILIENSIS

An atypical strain of Paracoccidioides brasiliensis was obtained from a patient with disseminated paracoccidioidomycosis. This isolate, whic h has been maintained in the laboratory for 4 years by successive subc ultures (30-40 days) in Fava Netto medium, produces cerebriform coloni es characteristic of the yeast phase of the fungus when left at room t emperature. Microscopy shows a predominance of yeasts with multiple bu ds, side by side with some branching filamentous structures presenting intercalary chlamydospores. The strain does not develop well at 37 de grees C, suggesting heat sensitivity. Storage at 4 degrees C does not change its macro- or microscopic characteristics. These findings suppo rt the hypothesis raised by others that the dimorphism of P. brasilien sis may not be exclusively heat dependent. Studies are currently being developed in our laboratory to better characterize this isolate in te rms of biochemical peculiarities, degree of virulence and susceptibili ty/resistance to antifungal drugs.