Molecular-Based Diagnostics Platform Rapidly Identifies Candidemia

The rapid results should enable clinicians to provide early, effective, and appropriate antifungal therapy for patients with Candida infections.

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

Candidemia, a bloodstream infection caused by Candida species, is one of the most serious hospital acquired infections, afflicting over 24,000 patients in the United States alone every year. Immunocompromised transplantation, oncology, and AIDS patients are especially at risk for contracting the infection with mortality rates as high as 50%.

Identification of Candida species is used to guide effective antifungal therapy--conventional laboratory methods can take up to five days or longer. The new assay, Yeast Traffic Light PNA FISH, developed by AdvanDx, (Woburn, MA, USA), will enable laboratories to rapidly detect, in a single test, up to five Candida species directly from positive blood cultures including C. albicans, C. Parapsilosis, C. tropicalis, C. glabrata, and C. krusei in hours instead of days.

A study led by Phyllis Della-Latta Ph.D., director of the clinical microbiology service at Columbia University Medical Center (New York, NY, USA; www.cumc.columbia.edu), demonstrated that rapid identification of C. albicans led to changes in the antifungal therapy being administered to patients. At the same time, rapid identification of C. glabrata, a species with high levels of resistance to fluconazole, led to an 81% switch to caspofungin for those patients who had otherwise been given fluconazole.

Based on the study results, the authors concluded that the PNA FISH test "can impact the appropriate selection of the most effective antifungal therapy, thereby making it a clinically relevant diagnostic assay.” The study was presented at the European Congress of Clinical Microbiology and Infectious Diseases (ECCMID) held in Barcelona, Spain, from April 19-22, 2008.

AdvanDx submitted Yeast Traffic Light PNA FISH for U.S Food and Drug Administration (FDA; Rockville, MD, USA) 510(k) clearance for the detection of Candida species in positive blood cultures


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