Conventional versus molecular diagnostic tests

In this session, emphasis was placed on the diagnosis of various mycoses through the identification of antibodies and antigens in sera, as well as on new techniques to properly identify medically important fungi through molecular biological procedures. The use of restriction fragment length polymorphism (RFLP) on fungal mitochondrial DNA (mtDNA) has enabled the identification of different strains of Sporothrix schenkii, several dermatophytes, Candida spp. and black fungi according to their species-specific mtDNA-RFLP patterns. In some species, distinct specific types where found in relation to the geographic origin of the patients. These particular molecular diagnostic tests are useful in the identification of strains and in epidemiological studies. An account of the applications of serological methods in the diagnosis of paracoccidioidomycosis was presented. Serology has been used in the identification of paracoccidioidomycosis using a specific, sensitive and rapid antibody-based immunodiagnosis method. Using the gp43 antigen, the diagnostic coverage of inmunodifussion has been improved from the 93-95% achieved with crude antigens, to 100% in an enzyme-linked immunodiffusion assay capture test. Cross-reactions were eliminated by treatment of the antigen with sodium metaperiodate. Antibody detection is useful, especially in paracoccidioidomycosis and histoplasmosis.