SIMPLIFIED HOST DNA REMOVAL PROCEDURE FOR VIRAL DETECTION IN CLINICAL BLOOD SAMPLES

Identification of pathogenic viruses with accuracy and speed in clinical samples for diagnosis is crucial to prevent a disease outbreak. In a typical blood sample, the amount of host nucleic acids in vast excess compared to pathogen nucleic acids makes identification of an unknown pathogen extremely difficult and time consuming. In this study, we investigated the efficiency of DNase I and Omnicleave nucleases together with different centrifugation speeds to remove host DNA in plasma and serum samples spiked with dengue virus type-1 (DENY-1). The quantities of DENY-1 RNA and contaminating human DNA were evaluated by qRT-PCR and Qubit (R) fluorometer, respectively, to determine the most efficient procedure for host nucleic acid removal. Enzymatic digestion was inefficient in removing host DNA from plasma and serum samples, similarly, using low-speed (6,200g) centrifugation by itself, with 10% average reduction. The most effective procedure was a combination of low- and high-speed (23,500g) centrifugation steps, achieving 80% reduction in host DNA for both DENY-1 spiked plasma and serum samples. The procedure is rapid, simple to perform and can be easily incorporated into any DNA extraction workflow.