| Congresso Brasileiro de Microbiologia 2023 | Resumo: 127-1 | ||||
Resumo:The consumption of food contaminated by pathogenic microorganisms, such as Escherichia coli and Klebsiella pneumoniae, is largely responsible for causing foodborne diseases (FBDs). The growing resistance of these bacteria to conventional antibiotics has raised concern in the scientific community, instigating the search for more effective treatment alternatives. In this context, antimicrobial peptides (AMPs) have stimulated research interest due to their remarkable antibacterial and antifungal activity. The peptide Lys-[Trp6]-Hy-a1 (Lys-a1), derived from hylin-a1 from the frog Hypsiboas albopunctatus, has shown promising antimicrobial activity, becoming the object of several studies. Thus, the aim of the present work was to evaluate the antibacterial activity of Lys-a1 combined with oxacillin (OXA) against a panel of E. coli (C22, C27, C55 e ATCC 11303) and K. pneumoniae (C17, C21, C28 e ATCC 700603) previously isolated from fresh shrimp. The antibacterial activity was assessed by microdilution broth to determine the minimum inhibitory and bactericidal concentration (MIC/MBC), as well as the time-kill curve, synergistic effect of the peptide with oxacillin (OXA) and gentamicin (GNT) by checkerboard assay, and pre-formed biofilm activity (48 hours). All tested strains showed sensitivity to Lys-a1, with MIC ranging from 23.4 to 93.7 µg/mL, while MBC ranged from 1 to 2 times the MIC values for most tested strains, except for the E. coli ATCC 11303. The bactericidal effect, as observed from the time-kill curve, was achieved between 180 and 240 minutes of contact with the peptide at MBC amounts. Additionally, a synergistic effect was observed only when combining Lys-a1 with oxacillin for most tested strains (5/8). Lastly, the Lys-a1/OXA combination showed a significant reduction in the pre-formed biofilm of the tested enterobacteria strains, demonstrating the action of Lys-a1 peptide on the strains and its potential use as an adjuvant in combating FBIs. However, it is important to highlight the need for further studies to elucidate the mechanisms of action and safety of these therapeutic combinations, as well as their clinical application. Palavras-chave: Antimicrobial peptides, Pharmacoresistance, Synergism, Escherichia coli Agência de fomento:Fundação Cearense de Apoio ao Desenvolvimento Científico e Tecnológico (FUNCAP) | |||||