Genotypic identification and characterization of species and strains within the genus Candida by using random...

Random amplified polymorphic DNA (RAPD) was used to better characterize the genotypic relatedness among medically important Candida species. By using short oligomer primers (10-mers) with arbitrarily chosen sequences in the polymerase chain reaction, distinctive and reproducible sets of polymerase chain reaction products were observed for isolates of C. albicans, C. lusitaniae, C. tropicalis, and Torulopsis (Candida) glabrata. The RAPD analysis differentiated a physiologically homogeneous panel of C. parapsilosis into three distinct groups and showed genetic diversity within C. haemulonii. Intraspecies DNA-length polymorphisms were seen for RAPD profiles derived from different isolates of each species. Analysis of RAPDs from a panel of C. albicans, which included 16 laboratory derivatives of two reference strains, showed that the profiles of unrelated strains differed and that the derivatives of each reference strain were identifiable. Minor differences in the RAPD profiles, suggestive of mutations that had occurred during the long-term maintenance of the strains, were detected. Because of its ease and reliability, RAPD analysis should be useful in providing genotypic characters for taxonomic descriptions, for confirming the identities of stock isolates, for typing Candida species in epidemiologic investigations, and for use in the rapid identification of pathogenic fungi.