What is the principle of LOOXSTER®?
Whole blood samples of sepsis patients contain complex DNA mixtures with a high human DNA background causing a very low bacterial plus fungal/human DNA ratio (1:2 x109). At first, a total cell lysis protocol is performed. The following concentration step uses the PUREPROVE® affinity chromatography incorporated in LOOXSTER®. PUREPROVE® is based on a DNA binding protein which recognizes definite unmethylated CpG motifs (A/T[CpG]A/T). Those motifs are predominantly present in bacterial and fungal genomes with different frequencies: • Bacteria: 1:50 • Fungi: 1:160 • Human: 1:2,200 A PUREPROVE®-based matrix removes more than 90% of the human background DNA. The final bacterial plus fungal/human DNA ratio is significantly higher in favor of the first, which substantially increases the sensitivity of downstream PCR methods and simultaneously reduces the time-to-result.
