Banca de DEFESA: NIELY PRISCILA CORREIA DA SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : NIELY PRISCILA CORREIA DA SILVA
DATE: 22/02/2022
TIME: 10:00
LOCAL: Remoto (Google Meet)
TITLE:

Development of chitosan polymeric nanoparticles with essential oil as an antimicrobial alternative against bovine mastitis

KEY WORDS:

Essential oils, Staphylococcus aureus, Chitosan, Nanotechnology.

PAGES: 60
BIG AREA: Ciências Agrárias
AREA: Medicina Veterinária
SUBÁREA: Medicina Veterinária Preventiva
SPECIALTY: Doenças Infecciosas de Animais
SUMMARY:

Bovine Mastitis (BM) is an inflammation of the udder tissue that affects milk production. The main etiological agents causing MB are pathogenic bacteria, and their main treatment is through antibiotic therapy, but the indiscriminate use of these drugs has favored the selection of bacteria with mutations that make them resistant, in addition to increasing the risk of residues of these compounds in milk. Therefore, the present work aimed to develop antimicrobial products nanoencapsulated in chitosan produced from the combination of essential oils from commercial plants commonly used in the treatment of bovine mastitis. Thirty strains of Staphylococcus aureus were collected and isolated from the milk of cattle diagnosed with mastitis. All strains were evaluated for resistance to different types of essential oils with a possible antimicrobial activity using the disk diffusion method. Among the other oils tested, the ones that presented consistent and efficient results were the EOs of Cymbopogon flexuosus, Thymus vulgaris, and Origanum vulgaris. Minimum inhibitory concentration (MIC) tests were performed and their values were defined ranging from 0.313 mg/mL to 1.250 mg/mL, to confirm the antibacterial activity of the oils, then the synergy of the antimicrobial activity of the different associated EOs was analyzed by the simplex-centroid-design design as a basis for evaluating the interaction between the chemical compounds, and indicated that the combined O. vulgare and T. vulgaris oils showed more consistent results against the four strains of S. aureus. Based on these results, a cream containing a mixture of these oils was produced, in which it is suggested that a percentage of 75% of O. vulgare and 25% of T. vulgaris be considered in the composition to optimize the antimicrobial activity of the mixture of oils. Subsequently, nanoparticles were produced by nanoprecipitation process by magnetic stirring containing a solution of chitosan in acetic acid. The produced nanoparticles were homogeneous, fluid, without color and odor change and size from 43 nm to 220 nm, thus characterizing themselves as nanoparticles. The PDI values ranged from 0.08 mV to 0.2 mV, which indicates good dispersion of the nanoparticles, while the zeta potential (ζ - mv) presented values from -1.48 mV to 6.47 mV, considering the zeta potential with the negative charge of -297 mV of S. aureus, it is suggested that nanoparticles with positive charge be used as an antimicrobial alternative, by eliminating possible electrostatic repulsions between the nanoparticle and S. aureus, thus allowing the inhibition of the bacterium. In addition, the nanoparticles can be incorporated into the base of the cream, thus allowing a controlled release of these EOs at the desired site of action.

BANKING MEMBERS:
Presidente - 2720914 - PABYTON GONCALVES CADENA
Interna - 2659103 - ELIZABETH SAMPAIO DE MEDEIROS
Externa ao Programa - 2170619 - MARILIA RIBEIRO SALES CADENA