Future diagnosis of sepsis : Evaluating the mNGS approach by using the MinION device
Abstract: Sepsis is an irregular systemic response to an infection, in which a pathogen or some of its component(s)reaches the bloodstream of the host or sterile tissue, triggering a disproportionate immune reaction. The first three hours are critical in the diagnosis of sepsis, in order to ensure an effective treatment with less impact on the patient. Culture-dependent diagnosis is the present standard procedure which can take up to several days. Metagenomics Next Generation Sequencing (mNGS) is a culture independent diagnostics method which could be used to identify the presence of pathogens from DNA extracted from human whole blood enabling a more effective treatment procedure of infected patients. The aim of this research was to utilize the sequencing data obtained with the MinION Nanopore sequencing device, in order to systematize its use as a tool for the early detection of sepsis; furthermore, determine if this technology is effective to use on DNA extracted from whole blood. The main research question of this thesis focused on whether the MinION Nanopore sequencing is a reliable tool for the early detection of sepsis. Whole blood samples from healthy donors was spiked with bacteria and DNA was extracted and sequenced with MinION device. The sequencing results were interpreted with the MinKNOW v2.0 software, through the application What’s In My Pot (WIMP). Also, the web tool PATRIC 3.6.12. and KRAKEN2 algorithm. The reads from the taxonomic family where the bacteria belong to was analyzed, presuming the bacterial DNA was present in the DNA extracted but the genus was not detected. According to the KRAKEN2 and WIMP analysis, the bacteria used to spike the whole blood samples was detected up to the taxonomic family level. Thus, confirming the presence of the spiked bacteria in the purified DNA samples.
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