COMPARISON OF MORPHOTYPIC AND GENOTYPIC METHODS FOR STRAIN DELINEATION IN CANDIDA

We compared two phenotypic methods, colony morphotyping on Sabouraud-t ripheniltetrazolium agar (STTZ) and serotyping; with two genotypic met hods, karyotyping and Random Amplified Polymorphic DNA bands obtained by PCR amplification (RAPD-PCR), for strain delineation in 33 Candida clinical isolates and two C. albicans strains from culture collections . Analysis of isolates on STTZ showed 11 different morphotypes. In two patients there was a switch in the morphotype coincidential with a ch ange in the susceptibility of the isolates to azole antifungals. C. al bicans isolates were divided into two serotypes. Sixteen and 18 differ ent patterns were identified among the Candida isolates by karyotyping and RAPD-PCR, respectively. No relationship was found between any of the typing methods used and the source of the isolates. The combinatio n of karyotyping and morphotyping on STTZ yielded useful epidemiologic al information, since It allowed the differentiation among the Candida species studied and the discrimination of clusters within C. albicans as well as to check the capacity of a strain to generate variants wit h different susceptibility to some antifungals.