Banca de DEFESA: JÉSSICA DE CRASTO SOUZA CARVALHO REIS

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : JÉSSICA DE CRASTO SOUZA CARVALHO REIS
DATE: 14/11/2025
TIME: 14:00
LOCAL: Sala de Seminários da Pós-Graduação no Departamento de Medicina Veterinária
TITLE:

Glanders in equines: genotypic characterization, virulence analysis, antimicrobial resistance of Burkholderia mallei, and evaluation of a vaccine platform with extracellular vesicle technology.

KEY WORDS:

Genotyping; Immunogen; Zoonosis; Equids.

PAGES: 95
BIG AREA: Ciências Agrárias
AREA: Medicina Veterinária
SUBÁREA: Medicina Veterinária Preventiva
SPECIALTY: Doenças Infecciosas de Animais
SUMMARY:

Glanders is a notifiable zoonosis caused by the bacterium Burkholderia mallei, which primarily affects equids and represents both a sanitary and economic challenge, as well as a public health risk. Considering the lack of effective vaccines and the diagnostic complexity of the disease, this study aimed to perform the genotypic characterization of two B. mallei strains (BmBr01 and BmBr02) isolated from equines with confirmed diagnosis, analyzing genetic variability, virulence factors, and antimicrobial resistance mechanisms, as well as to recover and characterize Extracellular Vesicles (EVs) produced by different isolates and evaluate their immunogenic properties. Genomic sequencing revealed high identity with the B. mallei Turkey2 strain, with Average Nucleotide Identity (ANI) values of 99.9018% and 99.9072% for BmBr01 and BmBr02, respectively. Genes associated with virulence were identified, particularly those related to type IV pili-mediated motility and type III (T3SS) and type VI (T6SS) secretion systems, with BmBr01 presenting a broader repertoire of these systems. Both strains exhibited identical gene profiles for lipopolysaccharide (LPS) biosynthesis and antimicrobial resistance, including vanR, vanH, penA, dfrA3, aac(6’)-Iak, and tetA(48), while BmBr01 showed greater diversity of genes associated with efflux pumps and resistance regulation, such as mexT, oprM, mdtE, mdtK, sdiA, and ompR. These findings indicate that BmBr01 displays greater adaptive plasticity, which may confer a selective advantage under antimicrobial pressure. EVs isolated from the BmBr01, BmBr02, and BAC/8619 strains predominantly measured between 100 and 200 nm and, when used to stimulate human monocyte-derived macrophages (THP-1), promoted a significant increase in IL-6 production. In cultures of human peripheral blood mononuclear cells, exposure to EVs resulted in enhanced mitochondrial activity and increased TNF and IFN-γ levels, suggesting a Th1-type immune response. In conclusion, the Brazilian B. mallei strains evaluated exhibit relevant genomic diversity and a gene repertoire associated with virulence and antimicrobial resistance, while their extracellular vesicles demonstrate in vitro immunogenic potential, representing a promising strategy for vaccine development against glanders.

COMMITTEE MEMBERS:
Presidente - RINALDO APARECIDO MOTA
Interno - JOSE WILTON PINHEIRO JUNIOR
Externo à Instituição - JONH ALDSON BEZERRA TENORIO
Externo à Instituição - MARCUS VINÍCIUS DIAS FALCÃO
Externa à Instituição - THAIS FERNANDA DE CAMPOS FRAGA DA SILVA - UFAL