Atividade antimicrobiana de Trichoderma spp. de origem amazônica contra fungos e bactérias de importância médica

Abstract

Antimicrobial resistance is a worldwide public health problem, since several species of pathogenic or opportunistic microorganisms have become resistant to several drugs available on the market, this occurs among other factors, due to the extensive and indiscriminate use of antibiotics and antifungals. Infectious diseases are among the main causes of morbidity and mortality in men and animals, so the search for new drugs of natural origin for more efficient treatments, less toxic and with a broad spectrum of antimicrobial action has gained more and more space in the search. Given this, the objective of this work was to evaluate the potential of antimicrobial activity of Trichoderma strains from the Amazon region against bacteria and fungi of medical interest. For this, the antimicrobial potential of the selected strains was initially evaluated as a solid medium by the agar block method against six bacteria, a yeast and a filamentous fungus. Subsequently, three strains of Trichoderma were selected that showed antimicrobial activity and were grown in two liquid media: Potato-dextrose modified with 2% yeast extract (BD) and Wheat bran (FT) to obtain metabolite extracts with solvent Acetate of ethyl. After cultivating and obtaining the extracts, the minimum inhibitory concentration (CIM), the minimum bactericidal concentration (CBM) and the minimum fungicidal concentration (CFM) of the obtained extracts were evaluated. Then, the toxicity test was performed on Artemia salina nauplii. All Trichoderma strains evaluated in the agar block showed inhibition of at least one of the six bacteria tested with different sizes of inhibition halos. Likewise, all strains showed activity against yeast, however none was able to inhibit the filamentous fungus. The CMI and CBM of the extracts ranged from 0.03 μg.mL -1 to > 2.0 μg.mL -1 , however the CFM found was 1.00 μg.mL -1 . In the toxicity tests of Trichoderm a extracts, no toxic activities were observed against Artemia salina nauplii in the evaluated concentrations. In view of the results presented, it was observed that the Trichoderma strains evaluated in this work are promising, as they present efficient antimicrobial activity against the tested microorganisms.