| Congresso Brasileiro de Microbiologia 2023 | Resumo: 459-1 | ||||
Resumo:Staphylococcus aureus is associated to a broad range of infections, not only in healthcare setting, but also in community-associated diseases. It has an impressive set of virulence factors, among them its ability to form biofilms in host tissues and medical devices. Targeting biofilm formation and maintenance is a promising alternative antimicrobial strategy. Marine microorganisms are source of pharmacologically active metabolites due to their biodiversity and capacity to produce unique metabolites in a competitive and exigent environment. This study aimed the application of metabolic profiling by LC-DAD-MS and statistical analysis to identify potential bioactive metabolites from Aspergilus welwitschiae FMPV28 associated to marine organism against S. aureus.
A. welwitschiae FMPV 28 was obtained from marine sponge Taedania sp. collected in Ponta Verde reef, Alagoas, Brazil. After metabolites production under static conditions mycelium was extracted with methanol and ethyl acetate was used to extract metabolites from culture medium. Organic solvents were evaporated and extracts were lyophilized. Extracts were identified as M28 (methanolic extract) and O28 (Ethyl acetate extract). M28 was submitted to chromatography in Sephadex™ LH-20 eluted with water-methanol and water-acetone gradients. Bacterial suspension of Staphylococcus aureus ATCC 25904 (strong biofilm-former) was used in the assays and biofilm formation was evaluated using crystal violet assay methodology. Metabolomic profile was determined by LC-DAD-MS, and statistical analysis (multivariate and chemometrics) were applied to correlate biological activities and chemical compounds.
Extracts M28-7 and O28-7 obtained from A. welwitschiae were initially evaluated for antibacterial and anti-biofilm activity against S. aureus. Interestingly, O28-7 has shown significant antibacterial activity, inhibiting completely bacterial growth, while M28-7 revealed only a slight effect on S. aureus Newman growth, but it significantly inhibited biofilm formation when compared to untreated control. M28 was submitted to bio guided fractionating procedures, searching for antibacterial and/or antibiofilm activity against S. aureus, resulting in 8 fractions. Four of them were able to inhibit S. aureus biofilm formation in 70% or more, without interfering in bacterial growth. Metabolomic profiling, allied to statistical analysis, allowed to correlate chemical compounds and biological activities. Regarding to antibiofilm activity, Principal Component Analysis (PCA) separated active and inactive fractions, and revealed two chemically different active clusters. PLS-DA data exhibited good separation and predictability of active and inactive antibiofilm samples. Fraction O28-7, the only one presenting strong antibacterial activity, revealed to be chemically distinct from the others and constituted mainly by more polar components. The variable importance in projection (VIP) and univariate statistical analyses using Pattern Hunter revealed that compounds like peptides and polyketides, and tensidol B, a furopyrrol, are strongly correlated to antibiofilm activity against S. aureus. These innovative approaches can be useful in identifying groups of secondary metabolites related to antibiofilm activity and, thus, orientate future research.
Palavras-chave: Aspergillus, Biofilm, LC-DAD-MS, metabolomic, Staphylococcus aureus | |||||