Determining the limit of detection for the iCatcher 12 system using microorganisms relevant for sepsis diagnostics in whole blood

Sammanfattning

For patients affected by sepsis, quick identification of the infectious microorganism is of utmost importance. Sepsis can be caused by as little as 1 CFU/ml in the bloodstream and current clinical molecular biology labs don’t possess reliable laboratory equipment that has the ability to detect microorganism concentrations this low. The new DNA-extraction robot;iCatcher 12, poses a solution. It has the unique benefit of having an above average input volume of 4 ml for whole blood extraction which significantly heightens the odds of successfully detecting a microorganism even in a sample with low concentration, at least in theory. For the purpose of determining the limit of detection for iCatcher 12, whole blood samples were spiked with microorganisms in a serial dilution ranging from 106 CFU/ml to 1 CFU/ml in a triplicated approach. After DNA-extraction with iCatcher 12 and two other extraction methods for comparison, the eluates were sequenced using nanopore sequencing technology and the findings declared that the limit of the detection for the iCatcher 12 reached as low as 100 CFU/ml. Further experimenting is required to lower the limit of the detection down to the desired concentration of 1 CFU/ml, perhaps by implementing a 16S/ITS PCR amplification step before sequencing.