Antimicrobial activity produced by filamentous fungi isolated from the waters of the Lower Tapajós River, Pará, Brazil

Abstract

Studies in Amazonian aquatic environments are incipient regarding the investigation of antimicrobials produced by filamentous fungi. This study qualitatively assessed the antimicrobial potential of fungi from the Lower Tapajós River Basin, Pará, Brazil. The collection was conducted at various points in the Lower Tapajós River Basin, from which fifteen fungi were selected. The strains were subjected to fermentation in Potato Dextrose Broth culture medium and filtered after 15 days of incubation. Using the Cup Plate method, aliquots of 100 μL of the crude broth were added to wells (6 mm in diameter) drilled into Petri dishes (90 mm in diameter) containing specific culture medium for the ATCC strains used in the tests (Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, and Candida albicans ATCC 60193). For technique validation, specific commercial antibiotics against the bacteria, as well as for the yeast, were used as positive controls. As a negative control, the solvent of the standard solution was used without the addition of the antibiotics used against the tested strains. Aspergillus sp. BBRT 01 stood out for exhibiting antimicrobial activity against all three tested microorganism strains. Additionally, Paecilomyces sp. BBRT 11, Penicillium sp. BBRT 12, and Penicillium sp. BBRT 13 demonstrated antimicrobial action against S. aureus. Fusarium sp. BBRT 09 displayed activity against C. albicans and S. aureus. In light of the results, it is noteworthy that filamentous fungi from the Lower Tapajós River Basin exhibited potential for bioprospecting bioactive substances and represent a horizon for research involving the Amazonian rivers.