| Congresso Brasileiro de Microbiologia 2023 | Resumo: 1043-2 | ||||
Resumo:Escherichia coli is a gram negative bacillus commensal of the human intestinal microbiota, but it also presents pathogenic strains. Pathogenic strains of E. coli cause intestinal infections, promoting diarrhoea, Crohn's disease, enteric and haemorrhagic syndromes, and outbreaks of water-borne and foodborne illnesses. These infections may be associated with another underlying disease, injury, or hospitalization in intensive care units with specific and difficult-to-treat clinical conditions, causing morbidity and mortality and medical care expenditure. To treat these infections, new molecules are studied, including quercetin, a flavonoid abundant in fruits and vegetables, however, its use becomes limited due low bioavailability and high hydrophobicity. To overcome these limitations, encapsulating quercetin in zein nanoparticles becomes a promising alternative in the use of oral particles for controlled release of antimicrobials to treat intestinal infections caused by E. coli strains. Thus, this study aimed to evaluate the antibacterial activity of zein nanoparticles encapsulated quercetin (QUER-ZNP). The QUER-ZNP were prepared by the method of nanoprecipitation and characterized by measuring the particle size (Ø), polydispersity index (PDI), zeta potential (ξ), pH and encapsulation efficiency (EE%). The determination of the minimum inhibitory concentration (MIC) of QUER and QUER-ZNP against Escherichia coli ATCC 25922, Escherichia coli NCTC 13846 and Escherichia coli H100407 strains was performed by the broth microdilution method according to the Clinical and Laboratory Standards Institute. The minimum bactericidal concentration (MBC) was determined from the well in which the MIC showed no growth bacteria, which an aliquot was seeded in Müeller Hinton agar (MHA) and incubated at 35 ± 2 ºC for 24 h. After this period, MBC was determined as the lowest concentration in which there is no microbial growth. The QUER-ZNP presented Ø of 252.6 nm, PDI of 0.071, ξ of -42.2±0.3 mV, pH 7.1 and EE% was 99.71%. The MIC of QUER and QUER-ZNP were 500 µg/ml and 31,25 µg/ml, >2000 µg/ml and 125 µg/ml, and >2000 µg/ml and 62,5 µg/ml for E. coli ATCC 25922, E. coli NCTC 13846 and E. coli H100407, respectively. The MBC of QUER were >2000 for all bacteria tested, while for QUER-ZNP were 64,5 µg/ml, 500 µg/ml, and 250 µg/ml for E. coli ATCC 25922, E. coli NCTC 13846 and E. coli H100407, respectively. Quercetin encapsulated into zein nanoparticles has greater antibacterial potential, making it a promising nanobiotechnological alternative for the development of a pharmaceutical product focused on the treatment of intestinal infections caused by E. coli strains. Palavras-chave: Gram-negative bacteria, intestinal infection, nanostructure, natural products Agência de fomento:National Council for Scientific and Technological Development (CNPq), Coordination for the Improvement of Higher Education Personnel (CAPES) and Foundation for the Support of Science and Technology of the State of Pernambuco (FACEPE). | |||||