Caracterização de fungos intestinais cultiváveis e avaliação da estrutura da micobiota intestinal humana de indivíduos obesos, com sobrepeso e eutróficos

Abstract

Fungi have a complex role in the intestinal tract, directly influencing health and disease and potential dysbiosis could contribute to obesity. The aim of this study was to investigate the fungal diversity of human gut microbiota among eutrophic, overweight, and obese individuals and to understand the gut microbial ecology shifts between healthy and obese individuals. Stool samples of 72 adult individuals were collected and dependent and independent cultive approach were performed to evaluate the fungi. The yeasts were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and the filamentous fungi were identified by microculture. The mean count of filamentous fungi and yeast was 1.58 log10 CFU/g of feces. Significant differences in the population level of the filamentous fungi was observed within eutrophic and obese groups. Overall, 34 genera were identified. The predominant phylum was Ascomycota with 20 different genera, followed by Basidiomycota and Zygomycota. The most prevalent specie was Paecylomyces sp. in euthrophic individuals and Penicillium sp. in obese individuals. The results of the eutrophic individuals suggest a slightly higher diversity of fungi within these individuals. Female individuals had a greater diversity of fungal types compared to males. The denaturing gradient gel electrophoresis (DGGE) analysis showed the grouping of eutrophic and overweight individuals in one cluster and of obese individuals in another cluster, although richness was low in all three groups. The fluorescence in situ hybridization (FISH) analysis showed a higher relative density of C. albicans in the obese group when compared to eutrophic and by the quantitative real time PCR (qPCR) a larger number of DNA copies of fungi and the phylum Ascomycota in obese individuals when compared to overweight and obese individuals. There was a positive correlation between fungi and the anthropometric parameters, total cholesterol, LDL, triglycerides, hemoglobin, HOMA-IR, HOMA-β, insulin, serum glucose, creatinine and percentage of dietary fibers and carbohydrates. Other studies are needed to better understand the causal relationship between gut mycobiota and obesity. This knowledge could be used in modulating the gut mycobiota and identifying future obesity treatments.