Banca de DEFESA: TALYTA NALDESKA DA SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : TALYTA NALDESKA DA SILVA
DATE: 30/11/2022
TIME: 09:00
LOCAL: Goole meet
TITLE:

Evaluation of the effects of saline extract and lectin from leaves of Schinus terebinthifolia Raddi on Staphylococcus

KEY WORDS:

Brazilian pepper tree, Staphylococcus aureus, mastitis, resistant microrganism, plant extract, lectin

PAGES: 83
BIG AREA: Ciências Agrárias
AREA: Medicina Veterinária
SUBÁREA: Medicina Veterinária Preventiva
SPECIALTY: Doenças Infecciosas de Animais
SUMMARY:

Antibiotics currently used to treat mastitis can affect the udder health and lead to the emergence of resistant microorganisms. The saline extract of Schinus terebinthifolia leaves (ES) and the lectin isolated from it (SteLL) have been previously reported as antimicrobial agents. The aim of this Dissertation was: 1. To carry out a narrative review on the action of plant compounds against mastitis-causing agents; 2. To investigate the effect of ES on Staphylococcus strains isolated from caprine mastitis and 3. To evaluate the antibacterial potential of SteLL against isolates of S. aureus sensitive (UFPEDA 02) and Oxacillin resistant (UFPEDA 670). Previously published studies were accessed in the main databases and a review article was created, considering the main mechanisms of antimicrobial action of plant compounds. S. terebinthifolia leaves were homogenized in 0.15M NaCl to obtain ES, and SteLL was isolated by chitin column chromatography. The effect of ES on the growth and survival of S. aureus strains isolated from mastitis (S. aureus 24 - Sa24, S. aureus 32 - Sa32, Staphylococcus sp. 1 - Ssp1 and Staphylococcus sp. 2 - Ssp2) was evaluated through determination of the minimum inhibitory (MIC) and minimum bactericidal (MBC) concentrations. Then, the growth curve of the isolates was determined and the antibiofilm activity of ES was investigated by the crystal violet method. The potential of ES for synergistic action with the antibiotics Carbapenem and Cephalexin was also evaluated. Additionally, the MIC and CMB values of SteLL against UFPEDA 02 and UFPEDA 670 were determined, and bacterial cell viability was investigated by flow cytometry. The antibiofilm potential of SteLL was also evaluated. The review revealed that the toxicity of plant antimicrobials for mastitis-causing agents mainly involves damage to the cell wall, lipid peroxidation, alteration of the transmembrane potential, oxidative stress, membrane pore formation and morphometric alterations that lead to apoptosis or increase in cell permeability. Antibiofilm activity may result from inhibition of microorganism adhesion, interference of quorum sensing autoinducers and/or exopolymer matrix degradation, damaging the three-dimensional structure of the biofilm. ES inhibited the growth of Sa24, Sa32, Ssp1 and SSp2 (MIC of 1800, 900, 450 and 225 μg/mL, respectively) but did not interfere with the survival of the isolates. The formation of biofilms by the isolates was impaired by ES, however the growth of planktonic cells was affected only in Sa32, Ssp1 and Ssp2 strains. ES also exerted synergistic action in combination with antibiotics against all isolates. SteLL was bacteriostatic and bactericidal agent for UFPEDA 02 and UFPEDA 670 isolates with MIC of 12.5 and 25 μg/mL, and CMB of 50 and 100 μg/mL, respectively. SteLL inhibited the growth in a dose-dependent manner and impaired morphometric parameters related to the size, shape, and cellular complexity of the sensitive and resistant strains, as well as inhibited the biofilm formation of UFPEDA 02 and UFPEDA 670. In conclusion, ES is an antimicrobial agent by affecting the growth and biofilm formation by mastitis isolates, and the toxicity of SteLL to S. aureus involves growth inhibition, induction of cell death and inhibition of biofilm formation.

COMMITTEE MEMBERS:
Presidente - EMMANUEL VIANA PONTUAL
Externa à Instituição - LIDIANE PEREIRA DE ALBUQUERQUE - UFPI
Externo à Instituição - NATALY DINIZ DE LIMA SANTOS - UFRPE
Externo à Instituição - THIAGO HENRIQUE NAPOLEÃO - UFPE