Diagnostic Test Rapidly Detects Candida

A nano-inspired platform has been developed that detects DNA from five of the most common Candida species found in patient blood.

The diagnostic platform based on T2 magnetic resonance, which is capable of sensitive and rapid detection of fungal targets in whole blood in approximately three hours, or up to 25 times faster than the current gold standard of blood culture.

A scientific team led by those from Brown University (Providence, RI, USA) studied the use of a novel diagnostic method based on T2 magnetic resonance (T2MR) to diagnose candidemia. The T2Candida assay uses blood-compatible polymerase chain reaction (PCR) to amplify Candida DNA, which then binds to superparamagnetic nanoparticles coated with a complementary DNA strand. The binding event causes the nanoparticles to cluster, which changes the sample's T2MR signal.

The investigators tested both Candida-spiked and patient samples and were able to rapidly, accurately and reproducibly detect five Candida species within human whole blood with a limit of detection as low as one colony forming units (CFU)/mL and a time-to-result of approximately three hours. Spiked samples showed 98% positive agreement and 100% negative agreement between T2MR and blood culture. Clinical samples demonstrated similar concordance with blood culture with the important distinction that T2MR was able to identify Candida species in the presence of antifungals, whereas blood culture could not.

The T2MR diagnostic platform is a product of T2Biosystems (Lexington, MA, USA) and using this system the scientists were able to detect down to three CFU/mL of C. albicans and C. tropicalis and even lower limits of detection for C. krusei, C. glabrata, and C. parapsilosis. From 24 patients’ whole-blood samples, they were able to correctly identify the eight candidemic patients, without any false-positive readouts from blood samples that contained bacteria.

Robert S. Langer, DSc, a professor and cofounder of T2 Biosystems, said, “T2MR represents a revolutionary, highly-sensitive nanotechnology solution, which can rapidly detect pathogens leading to early intervention that can save lives. T2Candida exemplifies the potential of nanotechnology to create great advances in healthcare in the near term.” The study was published on April 24, 2013, in the journal Science Translational Medicine.

Related Links:
Brown University
T2Biosystems