Prospect of Natural Antibiotic Products in Soil Microbiomes

Abstract

The search for new compounds that have antimicrobial properties has become increasingly important due to the growth and increase of multi-resistant microorganisms to drugs used in traditional medicine. A promising source of antimicrobials are microbial natural products, especially soil, an ecosystem that is home to about 59% of Earth's microorganisms and is responsible for 80% of antibiotics available on the market. New techniques have been developed for the cultivation and isolation of soil microorganisms, opening precedents for the investigation of hitherto little explored systems, as is the case of soil in Brazil, which has a rich biodiversity. In results obtained in a project currently under development in the laboratory, using soil from different locations on the USP Campus of Ribeirão Preto and employing the innovative technique of iCHIP for the isolation of microorganisms that are difficult to grow under laboratory conditions, it was verified, from in vitro tests, the presence of possible active compounds capable of inhibiting the growth of human pathogens. Thus, in this project, the prospection of compounds with antimicrobial activity will be carried out from six microorganisms isolated from the soil of the Cerrado and Atlantic Forest ecotone region. After the cultivation and growth of selected microorganisms, chromatographic fractionation techniques (SPE - solid phase extraction) and biological tests will be performed in order to identify active fractions against strains of Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans. To determine the chemical profile of fractions that show promising results, and isolation of active compounds, chromatographic and dereplication methods will be applied (HPLC-DAD-ELSD, HPLC-MS/MS). The isolation of the compounds will be performed by different chromatographic methods and the structural identification of the compounds will be based on spectroscopic and spectrometric data (NMR and MS).