| Congresso Brasileiro de Microbiologia 2023 | Resumo: 342-2 | ||||
Resumo:Emerging antimicrobial resistance (AMR) among bacterial pathogens leads to antimicrobial therapy failure and high mortality associated with AMR. The use of nanoparticles has grown due to several advantages, such as excellent biocompatibility and stability, small size, large surface area, in addition to presenting functional aspects, antimicrobial action, being able to assist in the treatment of diseases. The green biosynthesis of gold nanoparticles has been shown to be an effective, safe, ecological and economical procedure to replace conventional methods used for synthesis of nanoparticles. Studies show that probiotics, especially lactic acid bacteria (LAB), when they are in the intestinal microbiota, compete for binding sites, a mechanism of action that serves as a competitive exclusion strategy to prevent colonization by pathogenic bacteria. Therefore, the use of Pediococcus acidilactici CE51 in the synthesis of nanoparticles would be another viable technology with high biocompatibility for the treatment of infections caused by bacterial pathogens. The aims of this work were to synthesize gold nanoparticle (AuNP) with the use of cell free supernatant of probiotic strain (Pediococcus acidilactici CE51) and evaluate its antimicrobial effects in bacterial pathogens. The cell free supernatant from Pediococcus acidilactici CE51 was prepared with the inoculation of the fresh culture in MRS, incubated at 30°C for 24 h. The culture was centrifuged, the pH of the supernatant was adjusted to 8.5, and then submitted to sterile filtration. The supernatant obtained was used for the green synthesis of the metal (AuNPs). UV–vis absorption spectra, DLS and potential zeta were performed to characterize the nanoparticles. The evaluation of the antimicrobial action was performed using six strains of pathogenic microorganisms: Escherichia coli ATCC 35218, Staphylococcus aureus ATCC 29213, Listeria monocytogenes, Salmonella enterica subsp. enterica serovar Typhimurium ATCC 14028 and Pseudomonas aeruginosa ATCC 15442. A sample of 150 μL of each bacterium was inoculated in 3 mL of BHI broth and incubated at 37°C for 18-24h. The results were evaluated using plate count method in BHI agar and incubation at 37°C for 18-24h. The experiments were performed in triplicate. The AuNPs from Pediococcus acidilactici CE51 were found with a size of 259.2 ± 16.11 nm and zeta potential of −11.8 ± 4.69 mV. Gold nanoparticle from Pediococcus acidilactici CE51 completely inhibited the growth of all microorganisms tested when used in pure form. At concentration of 50% in BHI broth, it was noted a reduction of 1.5 log CFU/ml in S. enterica subsp. enterica serovar Typhimurium ATCC 14028 and P. aeruginosa ATCC 15442 growth. However, S. aureus ATCC 29213 and L. monocytogenes presented a reduction of about 1.0 log CFU/ml in plate count. There was no significant reduction E. coli ATCC 35218 growth in that concentration. The study concludes that these synthesized LAB-based nanoparticles have potential inhibitory effects and antibacterial properties against bacterial pathogens. Palavras-chave: Green biosynthesis, Gold nanoparticles, Pediococcus acidilactici CE51, Probiotic, Antimicrobial effect | |||||