Utility of the MagNA Pure 96 and LightCycler 480 Systems for Testing of Stool Samples for Toxin-producing <i>Clostridium difficile</i>

Clostridium difficile infection (CDI) is an important cause of hospital diarrhea. Conventional CDI testing by enzyme immunoassays is fast yet shows poor sensitivity and specificity, whereas the ‘gold standard’ toxigenic culture is laborious and time consuming. Molecular tests for CDI are fast and highly sensitive and specific. Our laboratory has developed a molecular procedure that allows for rapid detection of CDI directly in stool samples. It is based on the isolation of highly pure DNA extracts from feces using the MagNA Pure 96 System, followed by detection of the C. difficile toxins tcdA and tcdB using real-time PCR on the LightCycler® 480 Instrument. The easy to use pretreatment of feces combined with nucleic acid isolation on the MagNA Pure 96 System resulted in only 0.5% of inhibited samples. The positivity rate for CDI detection increased from 7.3% using conventional methods to 13.7% using real-time PCR. Nearly all PCR positive samples were confirmed by toxigenic culture, demonstrating the high specificity. With the MagNA Pure 96 System, handling steps were minimized and a high throughput and standardization were gained, causing less complexity, user interference and costs. March 2015 Arjan S. de Jong1, Eefje de Jong1, Patrick D.J. Sturm1 and Willem J.G. Melchers1 1 Department of Medical Microbiology, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands Utility of the MagNA Pure 96 System and LightCycler® 480 Instrument for Testing of Stool Samples on Toxin-producing Clostridium difficile