NEW YORK (GenomeWeb) – The US Food and Drug Administration cleared Roche's Cobas Cdiff Nucleic acid test last month for the detection of the toxin B (tcdB) gene of toxigenic Clostridium difficile on Roche's Liat platform, the agency said on its website.
Roche's test is an automated qualitative in vitro diagnostic test leveraging real-time PCR to detect the tcdB gene of toxigenic C. difficile in soft or liquid stool specimens obtained from patients suspected of having C. difficile infection. The test is intended as a diagnostic aid in conjunction with clinical and epidemiological risk factors, according to a document filed with the FDA.
The Cobas Cdiff detects tcdB target-specific and IC-specific oligonucleotide sequences. tcdB is a major toxin implicated in C. difficile pathogenesis and allows for the differentiation of toxigenic C. difficile strains from non-toxigenic strains, Roche said in its FDA document. It added that primers and probe oligonucleotide sequences were designed to detect C. difficile-conserved sequences without cross-reacting with other Clostridium genus organisms, or other organisms found in normal gut flora.
The test uses silica magnetic particle-based nucleic acid extraction and TaqMan probe-based real-time PCR amplification and detection. According to Roche, no reagent preparation or additional steps are required other than adding the biological sample in media to the Cobas Cdiff assay tube.