Rapid identification of yeasts commonly found in positive blood cultures by amplification of the internal transcribed spacer regions 1 and 2

A multiplex PCR method using one universal and eight species-specific primers was developed to rapidly identify eight yeast species found in positive blood cultures. The species-specific primers were designed from the internal transcribed spacer regions 1 and 2 of the rRNA gene, whereas the universal primer was located at the 26S rRNA gene. The eight species were Candida albicans, Candida glabrata, Candida guilliermondii, Candida krusei, Candida lusitaniae, Candida parapsilosis, Candida tropicalis, and Cryptococcus neoformans. The PCR products (116 to 630 bp) were different in length and could be effectively separated and recognized by polyacrylamide gel electrophoresis. By testing 234 positive blood cultures (237 isolates), 234 (98.7%) isolates of the above eight species were correctly identified by the multiplex PCR. The present method is simple to perform and can be completed within 6 h.