IDENTIFICATION OF CANDIDA SPECIES IN FORMALIN-FIXED, PARAFFIN WAX EMBEDDED ORAL-MUCOSA BY SEQUENCING OF RIBOSOMAL DNA

Aim-To identify Candida species in formalin fixed, paraffin wax embedd ed tissue by sequencing candidal rDNA. Methods-Target rDNA sequences w ere amplified by polymerase chain reaction (PCR) from fresh isolates o f Candida and from 18 preserved oral mucosal tissue samples (16 cases of chronic hyperplastic candidiasis and two fibroepithelial polyps), s hown histologically to contain Candida. Identification of Candida spec ies within tissue was based on a comparison of the rDNA sequences obta ined with those from the fresh isolates of Candida and those present i n the GenBank database. Results-The PCR products obtained from 12 of t he 18 tissue specimens studied were characteristic of Candida albicans . In two of these cases a second, larger PCR product was obtained and these sequences were characteristic of Candida glabrata. Conclusions-C andidal DNA was amplified successfully from formalin fixed, paraffin w ax embedded tissue. Sequencing of the PCR product enabled identificati on of the Candida species present.