Discovery of infection biomarkers based on metabolomics

• Autor(a) principal: Alexandre, Tiago Francisco Rosa Domingues
• Data de Publicação: 2022
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.21/16487
• topic: Biomarcadores; Infeção; Bacteremia; COVID-19; FTIR; Espetroscopia; Background and Goals: Critical COVID-19 patients are regularly admitted with diverse complications leading to Intensive care unit (ICU) admission. Besides these patients are constantly exposed to the threat of infection during their hospital stay. These infections may lead to the worsening of the patient’s health and considering the already debilitated state of the critical COVID-19 patient, may be fatal if the infection agent isn’t correctly identified and treated within the most appropriate timing upon diagnosis. In this thesis, the focus of the study was divided into two main sections: to determine a method capable of faster identification of bacteremia in the critical COVID-19 patient; and to identify Gram bacteria causing the bacteremia. Methodology: Utilizing the FTIR spectroscopy method, and spectra principal component analysis (PCA), hierarchical cluster analyses (HCA) and linear discrimination analyses (PCA-LDA) applied to serum samples of bacteremia patients (n=48), non-bacteremia patients (n=54), and samples with Gram-positive (n=28) from Gram-negative (n=20) bacteria. Diverse spectra pre-processing methods were evaluated. Results and discussion: Spectra PCA and HCA, did not shown samples patterns enabling to separate between bacteremia and non-bacteremia samples, nor between Gram-positives and Gram-negative bacteria. The high variability associated with these patients may justify the obtained result. Spectra PCA-LDA enabled discrimination accuracy results of 75% between bacteremia and non-bacteremia samples, and of 85% for discrimination between Gram-positive and Gram-negative bacterial samples. Final remarks: The results point to the potential of FTIR spectroscopy as a very appealing method to conduct the diagnosis of bacteremia and the classification of the type of bacteria, in a simple and rapid mode, enabling a more efficient management of this type of critical patients.; Biomarkers; Infection; Bacteremia; COVIID-19; FTIR; Spectroscopy

Thesis to obtain the Master’s degree in Biomedical Engineering