Test Rapidly Identifies Five Candida Species

An easy-to-use diagnostics platform rapidly identifies Candida yeast species directly from positive blood cultures.

The new assay, peptide nucleic acid fluorescence in situ hybridization (PNA FISH), is a highly sensitive, and specific assay that uses PNA probes to target species-specific ribosomal RNA (rRNA) in bacteria and yeasts.

Called the Yeast Traffic Light, the assay is the latest addition to AdvanDx's (Woburn, MA, USA) easy-to-use, molecular-based PNA FISH diagnostics platform that provides rapid identification of bloodstream pathogens in hours instead of days. Laboratories can identify, in a single Yeast Traffic Light test, up to five Candida species directly from positive blood cultures including C. albicans and/or C. parapsilosis, C. tropicalis, and C. glabrata and/or C. krusei in hours instead of days, enabling clinicians to provide early, effective and appropriate antifungal therapy for patients afflicted with Candidemia.

The results of the test indicate the yeast responsible for the infection; green fluorescing cells indicate C. albicans and/or C. parapsilosis; yellow fluorescing cells indicate C. tropicalis; and red fluorescing cells are C. glabrata and/or C. krusei.

It is important to identify the Candida species because they display varying resistance to commonly used antifungal agents. C. albicans and C. parapsilosis are generally susceptible to the antifungal drug fluconazole, C. tropicalis may display intermediate resistance to the drug while C. glabrata and C. krusei have the highest level of fluconazole resistance. Recent reports indicate that caspofungin, a newer and more expensive broad-spectrum antifungal drug, may be less potent against C. parapsilosis.

Candidemia, a bloodstream infection caused by Candida species, is one of the most serious nosocomial infections, afflicting over 24,000 patients every year in the United States alone. Immunocompromised transplantation, oncology, and AIDS patients are especially at risk for contracting Candida infections with mortality rates as high as 50%. Conventional methods for identifying the pathogen can take up to five days or more.

AdvanDx has received U.S. Food and Drug Administration (FDA; Rockville, MD, USA) 510(k) clearance of the Yeast Traffic Light PNA FISH to identify Candida yeast species directly from positive blood cultures.

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