| Congresso Brasileiro de Microbiologia 2023 | Resumo: 1280-1 | ||||
Resumo:Antimicrobial resistance is one of the biggest challenges for public health and prevents the achievement of several Sustainable Development Goals established by the World Health Organization. Natural products are important sources of new antimicrobial molecules and can be used alone or in combination with antibiotics, modulating bacterial resistance and boosting the activity of "usual" antibiotics. Eugenol (EUG) is a secondary metabolite responsible for providing the characteristic aroma to several plant species, and is known to have antimicrobial, anti-inflammatory, analgesic and antioxidant properties, which is why it arouses interest in different segments in the industry. The present study aimed to evaluate the antibacterial activity of EUG and its synergistic potential associated with antibiotics against strains of clinical importance. For the determination of the Minimum Inhibitory Concentration (MIC) of EUG (SIGMA-ALDRICH) and the antibiotics Amoxacillin (AMO), Cefalexin (CEF) and Ciprofloxacin (CIP) was determined against the clinical strains of Klebsiella pneumoniae (UFPEDA 396), Pseudomonas aeruginosa (UFPEDA 416) and Staphylococcus aureus (UFPEDA 02), using the broth microdilution method. The modulation of antibiotic resistance associated with EUG was determined by the checkerboard method through the determination of the Fractional Inhibitory Concentration (FIC). For the bacterial growth curve test, the strains were exposed to the MIC concentrations of the antibiotics and EUG over a period of 24 hours, as well as the concentrations obtained from the combinations that exhibited synergistic activity (2xFIC, 1xFIC and 1/FIC), and optical density readings were taken every hour to evaluate the effect of the treatments on bacterial growth. For all strains tested, EUG showed an MIC of 2000±0 µg/mL. However, for at least one of the antibiotics used, all strains showed high resistance, with the highest rates for CEF= >500±0 µg/mL and CIP=125±4 µg/mL for K. pneumoniae, CEF= 500±0 µg/mL for P. aeruginosa and AMO= 32±2 µg/mL for S. aureus. According to the FIC, synergistic effects were obtained from the combination with EUG and AMO against S. aureus, with a reduction of the necessary concentration of the antibiotic by 93.75%. For CIP, EUG reduced by 48.78% the antibiotic concentration required to present antibacterial activity against K. pneumoniae. The growth curves demonstrate the reduction in bacterial load after 4h of experimentation, showing a better effect of the combined treatments of EUG and antibiotics compared to their isolated effects. This study demonstrated that EUG is a promising resource of new antimicrobial molecules, able to act alone or in combination with traditional antibiotics. The combination of the EUG with the antibiotics revealed notable synergistic effects in some situations, which highlights the importance of exploiting natural products for tackling antimicrobial resistance in order to develop effective and sustainable therapeutic approaches for the treatment of antibiotic-resistant infections. Palavras-chave: Antimicrobial resistance, Natural products, Antibacterial activity, Modulation of resistance Agęncia de fomento:Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) | |||||