Miniaturized Magnetic Resonance for Direct Diagnosis of Candida Infection in the Blood

An innovative approach for diagnosis of Candida infection directly from blood samples is based on miniaturized magnetic resonance technology and does not require any sample pretreatment or extraction.

T2 Biosystems, Inc. (Lexington, MA, USA) introduced its T2Candida Panel designed for use on the T2 Magnetic Resonance (T2MR) platform, the T2Dx, at the recent San Diego (CA, USA) joint meeting of the Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) and the International Society of Chemotherapy (ICC).

T2MR utilizes miniaturized magnetic resonance technology, which measures how water molecules react in the presence of magnetic fields. For molecular and immunodiagnostics targets it capitalizes on advances in the field of nanotechnology by deploying particles with superparamagnetic properties that enhance the magnetic resonance signals of specific binding events. When particles coated with target-specific binding agents are added to a sample containing the target, the particles bind to and cluster around the target. This clustering changes the microscopic environment of water molecules in that sample, which in turn alters the magnetic resonance signal, or the T2 relaxation signal that is measured, indicating the presence, absence, or concentration of the target.

Unlike most detection methods, T2MR can quickly and accurately identify molecular targets within patient samples without the need for purification or extraction of target molecules from the sample.

In a clinical study, specimens were collected from 23 patients on the day of enrollment and on days three, five and seven. Blood culture and T2Candida test results were compared to determine which method was most accurate for monitoring those patients.

Results revealed that T2Candida demonstrated greater accuracy in detecting invasive candidiasis, or the presence of the Candida infection, reporting 17 positive results during the testing period for nine patients with candidemia who were receiving antifungal therapy, while blood culture reported only three positive results within the same patient set. Overall, T2Candida demonstrated 91.1% sensitivity, 99.4% specificity, and limit of detection as low as one CFU/mL (colony forming unit per milliliter).

“Previous studies have demonstrated that blood culture may yield false negative test results when patients are on antifungal therapy,” said John McDonough, president and CEO of T2 Biosystems. “The results from this study demonstrate that T2Candida can provide more accurate results for patients who are on antifungals which can enable physicians to make better treatment decisions regarding the duration of therapy and controlling the source of the infection, including catheterization procedures and other medical interventions known to cause the disease.”

Details of the comparing the effectiveness of the T2Candida panel to blood culture were published in the September 15, 2015, online edition of the journal Future Microbiology.

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T2 Biosystems, Inc.