Banca de DEFESA: JOYCE NAYARA GOMES DA SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : JOYCE NAYARA GOMES DA SILVA
DATE: 26/02/2026
TIME: 09:00
LOCAL: Departamento de Biologia da UFRPE
TITLE:

Anti-infective and antibiofilm action of a formulation containing plant lectins and gentamicin for the
control of listeriosis

 

KEY WORDS:

Listeriosis, Phytotherapy, ConBr, CFL

PAGES: 64
BIG AREA: Ciências Agrárias
AREA: Medicina Veterinária
SUBÁREA: Medicina Veterinária Preventiva
SPECIALTY: Doenças Infecciosas de Animais
SUMMARY:

Listeria monocytogenes represents a clinical challenge, particularly because listeriosis can reach a lethality of up to 30% in susceptible individuals, a situation that may be exacerbated by the emergence of antimicrobial resistance. In this context, there is growing interest in natural compounds capable of modulating immune responses and enhancing the efficacy of conventional antibiotics. Lectins from Canavalia brasiliensis (ConBr) and Cratylia argentea (CFL) stand out due to their ability to recognize microbial glycoconjugates, influence cellular processes, and stimulate host defense mechanisms. Thus, this study investigates the synergistic potential of the CbCfLG formulation (ConBr + CFL + gentamicin) in in vitro and in vivo infection models, evaluating antimicrobial activity, cytotoxicity, the potential to reduce intracellular bacteria, leukocyte modulation, and efficacy in decreasing bacterial load in target organs. The results show that, although ConBr and CFL do not exhibit direct antimicrobial activity against L. monocytogenes, their combination with gentamicin lowers the minimum inhibitory concentration (MIC) of the antibiotic from 0.25 µg/mL to 0.125 µg/mL, while the minimum bactericidal concentration (MBC) decreased from 0.5 µg/mL to 0.25 µg/mL, revealing a significant influence of the lectins on bacterial susceptibility. Furthermore, it was observed that combinations containing 5 and 10 µg/mL of the lectins were capable of eliminating intracellular growth of L. monocytogenes in infected peritoneal macrophages. In vivo experiments showed that animals treated with the combination of 5 ConBr + 5 CFL + 10 Gen mg/kg exhibited a reduction in microbial load in the liver and spleen compared to treatment with gentamicin 10 mg/kg alone, indicating that at this ratio the lectins can modulate systemic pathogen clearance. Additionally, no significant weight loss was observed in groups treated with CbCfLG compared to the gentamicin-only group. Leukocyte quantification also indicated that doses of ConBr 5 and CFL 1 + Gen 10 mg/kg resulted in reductions in total leukocytes and neutrophils compared to the untreated group after three days of infection. It is concluded that the CbCfLG formulation exerts a significant effect on L. monocytogenes, enhancing gentamicin activity, promoting intracellular bacterial clearance, and reducing systemic bacterial load without apparent toxicity. These findings reinforce that plant lectins may act as promising therapeutic adjuvants in the control of listeriosis, opening perspectives for more effective combinatorial approaches against intracellular pathogens.

COMMITTEE MEMBERS:
Presidente - JOSE VITOR MOREIRA LIMA FILHO
Interno - JOAQUIM EVENCIO NETO
Externo ao Programa - 980615 - CLAUDIO AUGUSTO GOMES DA CAMARA - UFRPE