Antimicrobial effect of the postbiotic produced by Pediococcus acidilactici on Escherichia coli ATCC 25922

The increasing resistance of pathogenic bacteria to conventional antibiotics has necessitated the search for alternative antimicrobial agents. This study investigated the antimicrobial activity of postbiotic metabolites produced by Pediococcus acidilactici against Escherichia coli (ATCC 25922). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the postbiotics were determined using the broth microdilution method. Additionally, the disk diffusion and well diffusion methods were employed to evaluate the antimicrobial activity. The results demonstrated that the postbiotic metabolites exhibited significant antimicrobial effects, with a MIC of 62.5 μg/mL and a MBC of 125 μg/mL. Inhibition zones of 9.33 mm, 12.33 mm, and 12.33 mm were observed in the disk diffusion method at concentrations of 230, 250, and 270 μg/mL, respectively. In the well diffusion method, inhibition zones of 18 mm, 18.33 mm, 21.33 mm, and 23 mm were observed at concentrations of 250, 260, 270, and 280 μg/mL, respectively. These findings suggest that postbiotic metabolites from Pediococcus acidilactici have potential as alternative antimicrobial agents against Escherichia coli.