UNIQUE OLIGONUCLEOTIDE PRIMERS IN PCR FOR IDENTIFICATION OF CRYPTOCOCCUS-NEOFORMANS

On the basis of a comparison of rRNA sequences coding the internal tra nscribed spacer (ITS) and 5.8S regions of Filobasidiella neoformans, t he teleomorph of Cryptococcus neoformans, and members of its most clos ely related taxa, unique oligonucleotides were designed for the specif ic amplification of DNA only from C. neoformans. Various combinations of these primers, designated CN4, CN5, and CN6, and the previously des cribed fungal primers ITS1 and ITS2 were tested in PCR for their abili ty to amplify DNA from 37 strains of C. neoformans and 31 other isolat es representing 18 species of yeasts. The combination of primers CN4 a nd CN5 amplified DNA from both varieties of C. neoformans but from non e of the other species tested. Other pairs of primers (namely, CN5-CN6 , CN4-ITS1, and CN6-ITS1) amplified DNA only from C. neoformans and fr om the saprophyte Filobasidiella depauperata, which is the only other member of the genus Filobasidiella. With appropriate controls, these s pecific oligonucleotides may be used as primers in PCR to identify C. neoformans.