BIOESPECTROSCOPY ASSOCIATED WITH CHEMOMETRICS IN BACTERIAL STUDIES
Bioespectroscopy. SPA-LDA. GA-LDA. NIR. ATR-FTIR
This qualification exam is a contribution to the development of works that use biospectroscopy in conjunction with chemiometric tools. These two, together, encompass non-invasive, high-throughput, low-cost and objective techniques, and which has enormous potential in the analysis of bacteria, complementing or even replacing methods of diagnosis of diseases conventionally conducted by specialists by standard methods expensive and require specific reagentes. The data obtained from biospectroscopy in biological samples are complex and have many overlapping bands and it is necessary to apply mathematical tools to overcome these difficulties. For this, some mathematical tools, such as variable selection methods, that use linear discriminant analysis with successive projection algorithm (SPA-LDA) and genetic algorithm (GA-LDA) generally used for the purpose of solving this data, facilitating the extraction of information. Infrared spectroscopy, specific near infrared (NIR) and Fourier tranform-infrared with atenuated total reflectance (ATR-FTIR), together with variable selection techniques (SPA-LDA e GA-LDA) were used to discriminate bacterial (Staphylococus aureus, Klebsciela pneumonieae e Pseudomonas aeruginosa). Probable biomarkers such as lipids and proteins at ~1550 cm-1 and 1400 cm-1 and DNA vibrations at ~1080 cm-1 were obtained. Sensitivity values of 75% and 95% for SPA-LDA models and 100% and 93% for GA-LDA models were achieved. Based on these results, it can be concluded that SPA-LDA and GA-LDA in conjunction with infrared spectroscopy are efficient tools, improving the time and cost of diagnosis, making it possible to treat faster than standard methods and, consequently, avoiding the evolution of a possible infection.