ANÁLISE ESPECTROSCÓPICA (FTIR) DE CEPAS DE REFERÊNCIA DE LEISHMANIA SPP CAUSADORAS DE LEISHMANIOSE TEGUMENTAR

Abstract

Leishmaniases are recognized as emerging and highly neglected diseases, for which there are currently no control programs in place to contain their incidence. The causative agents are protozoan parasites belonging to the genus Leishmania. The wide variety of causative species and the host's immunological response result in a broad spectrum of clinical manifestations, which are classified as cutaneous leishmaniasis (CL), mucosal leishmaniasis (MCL or ML) and visceral leishmaniasis (VL). Optical spectroscopy techniques are becoming increasingly prominent in the field of infectious disease diagnosis. They facilitate the direct analysis of spectra obtained from biological samples, combined with non-invasive methodologies, enabling diagnosis in less time than traditional methods. The objective of this study was to improve the methodology for the identification of Leishmania spp. species that cause CL or ML, employing multivariate analysis of infrared absorption spectra. Additionally, the most significant spectral contributions were identified and associated with the biological components of the samples. The samples submitted for FTIR analysis were promastigote cultures of strains that had already been properly identified and characterized by conventional methods: Leishmania (Leishmania) amazonensis (IFLA/BR/1967/PH8) and Leishmania (Viannia) braziliensis (MHOM/BR/75/M2904). The mid-infrared absorption of the samples was evaluated (wavelength range of 600 to 000 cm-1) using an attenuated reflectance accessory for data collection, namely vibrational optical spectroscopy. Subsequently, the data were subjected to statistical multivariate analysis to facilitate the differentiation of the species and reference cells. A total of 37 samples of the parasite cultures were analyzed at different times using MATLAB R2015b software. The results demonstrated distinctions between the samples in the spectral regions between 1200 and 900 cm-1, as well as a region between 1028 and 1120 cm-1, which is associated with polysaccharide absorption. The cluster analysis, conducted using principal component analysis (PCA), revealed a distinct separation between the Leishmania species. The results suggest that FTIR analysis may serve as a viable diagnostic method for distinguishing between Leishmania species. This approach may facilitate more accurate diagnoses and more effective treatments for patients.