Rapid identification of Candida species in oral rinse solutions by PCR.
OBJECTIVE
To determine the sensitivity and specificity of a multiplex PCR assay for the contemporary identification of major species involved in oral candidiasis, without extraction and purification of DNA from the samples under investigation; and evaluation of this method in comparison with routine phenotypic culture identification.


METHODS
78 oral rinse solutions were collected. The concentrated oral rinse technique was used for a quantitative and qualitative study. Research and identification of Candida spp, with routine phenotypic culture identification (germ-tube test in serum at 37 degrees C for 3 hours and sugar assimilation strip analysis), were performed. Each sample was analysed with multiplex PCR directly on oral rinse solution. Samples giving discrepant results between routine phenotypic and PCR identification methods were resubcultured on CHROMagar Candida plates. The fungus-specific primers ITS1, ITS2, CA3, and CA4 were used. For the identification of other species (C kefyr, C famata and C dubliniensis), ITS1F, ITS1K, and ITS2D primers were designed.


RESULTS
Multiplex PCR correctly identified all samples, including those with single species, or with mixed species, negative samples and positive samples which appeared to be negative from routine phenotypic methods.


CONCLUSIONS
This multiplex PCR assay provides a rapid alternative to the conventional culture based technique for the identification and speciation of the most frequently isolated Candida species. The absence of an extraction method made identification of 10 species possible in a few hours.
Liguori
Giorgio
G
Chair of Hygiene and Epidemiology, Faculty of Movement Sciences, University of Naples Parthenope, Naples, Italy. giorgio.liquori@uniparthenope.it
Lucariello
Angela
A
Colella
Giuseppe
G
De Luca
Antonio
A
Marinelli
Paolo
P
D002175:Candida / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D002180:Candidiasis, Oral / Q000382:microbiology*; D004271:DNA, Fungal / Q000235:genetics; D006801:Humans; D009067:Mouthwashes; D016533:Mycological Typing Techniques / Q000379:methods; D016133:Polymerase Chain Reaction / Q000379:methods; D012680:Sensitivity and Specificity
D004271:DNA, Fungal; D009067:Mouthwashes