A test for Candida, a fungal infection that can lead to sepsis, identified the pathogen in whole blood samples in a few hours, rather than the two to five days needed by current tests. Researchers from T2 Biosystems, a biotechnology company in Lexington, Massachusetts, with colleagues from Brown University and Harvard University medical schools published their findings in this week’s issue of the journal Science Translational Medicine (paid subscription required).
Candida is a common source of hospital-acquired infections, a fungus that affects the blood stream, and is occuring more frequently to become the fourth most common pathogen found in blood cultures in the U.S. Candidemia, the infections resulting from Candida, can lead to sepsis, a dangerous life-threatening complication, where inflammation throughout the body can damage multiple organs and result in septic shock. Candida infections in the blood have a mortality rate of 40 percent, due largely from the extended time needed to test blood for the pathogen.
T2 Biosystems develops diagnostics using complex specimens like whole blood that combine nanotechnology, genomics, and magnetic resonance imaging (MRI), in a technology called T2MR. The test used in the study, known as T2Candida, harnesses polymerase chain reaction, a genomic technique that amplifies DNA in Candida and binds to nanoparticles, coated with a complementary strand of DNA. This binding action causes the nanoparticles with the amplified Candida DNA to cluster, making them detectiable with T2 Biosystems’ MRI technology.
In the paper, researchers were able to detect Candida species in human whole blood, in concentrations as low as 1 colony-forming unit per milliliter, in less than three hours. No pre-treatment or purification of the samples were conducted. Tests run with samples of various concentrations showed 98 percent agreement when Candida fungi were present and 100 percent agreement when absent.
The team also tested 21 blinded clinical specimens using the T2 method, which found similar results to traditional blood culture lab tests to detect infections. The T2MR technology, however, was able to detect Candida organisms in the presence of antifungal compounds, while blood cultures could not. The technology — still considered investigational and not yet approved by FDA for clinical use — is portable and automated, rather than relying on human visual judgements.
“T2MR represents a revolutionary, highly-sensitive nanotechnology solution, which can rapidly detect pathogens leading to early intervention that can save lives,” says Robert Langer, professor of biomedical engineering at MIT and co-founder of T2 Biosystems. The company’s founders include faculty from Harvard Medical School and Massachusetts General Hospital, as well as MIT.
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