| Congresso Brasileiro de Microbiologia 2023 | Resumo: 164-2 | ||||
Resumo:The antimicrobial resistance is considered a global public health problem, with high number of deaths caused by multidrug-resistant bacteria. One of the biggest medical concerns are methicillin-resistant S. aureus (MRSA) and vancomycin-resistant S. aureus (VRSA) strains. In addition, some studies to report infections caused by vancomycin intermediate S. aureus (VISA). Moreover, microorganisms have ability to form biofilm, a microbial community resistant. Biofilms have shown 10–1000 times more antibiotics resistance than the planktonic cells. In fact, the pace of development of new antimicrobials is not keeping up with antimicrobial resistance. Thus, the discovery of new compounds that are able to eradicate such biofilms is critical. In this sense, research with natural products has guided the discovery of antimicrobial compounds. The aim of this study was to evaluate the antimicrobial and antibiofilm activity of essential oil (EO) extracted from Lippia grata and, its association with ampicillin, against Staphylococcus aureus strains, as ATCC 25923, ATCC 700698 (MRSA) and JKD6008 (VISA). The extraction of essential oil from L. grata was performed by hydrodistillation process, using the Clevenger apparatus. The antibacterial activity was determined by microdilution methods. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the essential oil and ampicillin were determined by the broth microdilution assay in 96-well polystyrene. The evaluation of the associations between the essential oil and the antibiotic was performed using the checkerboard method. The antibiofilm activity of the EO and its association with ampicillin was evaluated by quantification of biomass total (crystal violet staining) and enumeration of biofilm-entrapped viable cells. Moreover, Structural assessments of the biofilms and cellular morphological changes were performed using scanning electron microscopy (SEM). The EO showed potential antimicrobial activity against planktonic cells, MIC at 2.5 mg/mL for the three strains of S. aureus and MBC at 2.5 mg/mL against S. aureus JKD6008. The EO association with ampicillin showed synergistic effect against three strains tested. Furthermore, the EO and its association with ampicillin were able to significantly reduce the biofilm formation and disrupt preformed biofilms. Moreover, the essential oil and ampicillin (individually and in association) altered the cellular morphology of S. aureus cells in biofilm. In conclusion, L. grata EO demonstrated antimicrobial activity against S. aureus strains. L. grata EO associated with ampicillin has the potential to contribute to the synthesis of antimicrobials against infections caused by S. aureus biofilms. Palavras-chave: Staphylococcus aureus, Biofilm, Essential oil, Antimicrobial activity Agência de fomento:Fundação de Amparo à Pesquisa do Estado de Minas Gerais | |||||