Banca de QUALIFICAÇÃO: ALEXANDRE BROL

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : ALEXANDRE BROL
DATE: 01/12/2023
TIME: 11:20
LOCAL: Web Conferência - Google Meet: meet.google.com/cym-bqcs-vot.
TITLE:

Antimicrobial Effect of Silver Nanoparticles.

KEY WORDS:

Salmonella spp.; Poultry; Biofilm; Bactericide.

PAGES: 45
BIG AREA: Ciências Agrárias
AREA: Medicina Veterinária
SUMMARY:

Multi-resistant microorganisms to conventional antimicrobial substances are becoming a problem in the poultry sector, such as Salmonella spp, responsible for high rates of morbidity and mortality, causing major economic losses. Therefore, a strategy currently used in veterinary medicine is the search for alternative antimicrobial substances, such as metallic nanoparticles. The objective of this work is evaluate the antimicrobial potential of silver nanoparticles, using pathogenic bacteria for poultry as test organisms. The silver nanoparticles were produced at the Instituto Federal Catarinense, Santa Rosa do Sul Campus, Santa Catarina, Brazil. The Antimicrobial activity was evaluated with inoculums standardized at 3 x 108 CFU/ml of gram-negative bacteria Salmonella enterica Enteritidis ATCC 13076, Salmonella enterica Typhimurium ATCC 14028, Salmonella enterica Heidelberg ATCC 8623 and Salmonella enterica Pullorum ATCC 13036, at the Biology Laboratory, Campus Concórdia, Santa Catarina, Brazil. Furthermore, 15 clinical isolates of S. Heidelberg from poultry were used, donated by an animal health laboratory located in the west of Santa Catarina, Brazil, were used. The methods used were the minimum bactericidal concentration (CBM) of silver nanoparticles at concentrations of 4000, 2000, 1500, 1000, 750, 500, 250, 125 and 62.5 mg/ml, using agar diffusion and broth microdilution techniques, followed by statistical analysis with the Tukey test (p < 0.05). Likewise, the biomass quantification method was used with crystal violet with optical density (OD) reading at 550 nm, followed of analysis to classify of bacteria with no biofilm producers (OD ≤ DOc), weak biofilm producers ( DOc < OD ≤ 2*DOc), moderate biofilm producers (2*DOc < OD ≤ 4*DOc) and strong biofilm producers (4*DOc < OD), being that the cut-off value (ODc) was defined as three standard deviations above the mean DO of the negative control. The results of CBM using the agar diffusion technique revealed that concentrations with inhibitor halos with statistically significant diameters in relation to control for the test organisms S. Enteritidis ATCC 13076, S. Typhimurium ATCC 14028, S. Heidelberg ATCC 8623 and S. Pullorum ATCC 13036 were 4000, 2000, 1500 and 1000 mg/ml. Therefore, concentrations 62.5, 125, 250, 500 and 750 mg/ml did not present statistically significant bacterial inhibition. Thereby, the MBC using the broth microdilution technique for the test organisms S. Enteritidis ATCC 13076, S. Typhimurium ATCC 14028, S. Heidelberg ATCC 8623 and S. Pullorum ATCC 13036 were 500, 1500, 1000 and 750 mg/ml, respectively. The results of bacterial biofilm quantification classified the standard strain of S. Heidelberg ATCC 8623 and the clinical isolates of S. Heidelberg as weak biofilm producers. According to the results, it is concluded that microorganisms were not capable of producers moderate or strong biofilms and that silver nanoparticles have bactericidal potential, enabling their use in the prevention or treatment of Salmonella spp. infections in the chicken production chain.

COMMITTEE MEMBERS:
Presidente - 1989957 - ALESSANDRA FARIAS MILLEZI
Interno - 2613308 - DELANO DIAS SCHLEDER
Interna - 1046884 - ELIZABETH SCHWEGLER
Interno - 1810731 - JULIANO SANTOS GUERETZ
Interno - 1755182 - MARIO LETTIERI TEIXEIRA
Interna - 2408296 - SORAYA REGINA SACCO