Antimicrobial activity of postbiotics from Pediococcus acidilactici against Pseudomonas aeruginosa (ATCC 27853)

Hamed Azad; Fatemeh Gavari; Pourya  Nezhad; Seyed Masoud Hashemi Karouei; Arian Ghasemi; Alireza Shabani; Isa Gholampour Azizi

doi:10.5455/EJMID.20250512091855

Abstract
Aim/Background: The rising antibiotic resistance of Pseudomonas aeruginosa necessitates alternative therapies. This study evaluated the antimicrobial efficacy of postbiotic metabolites from Pediococcus acidilactici against Pseudomonas aeruginosa (ATCC® 27853™).
Methods: Broth microdilution determined minimum inhibitory (MIC) and bactericidal (MBC) concentrations. Disk and well diffusion assays assessed antimicrobial activity. All experiments were performed in triplicate, with statistical analysis via ANOVA and Tukey’s post-hoc test.
Results: The postbiotics exhibited MIC and MBC values of 208.33 ± 5.77 µg/mL and 416.66 ± 10.41 µg/mL, respectively. Inhibition zones in disk diffusion increased dose-dependently (8.33 ± 0.58 mm at 480 µg/mL; 11.00 ± 1.00 mm at 520 µg/mL; p < 0.01). Well diffusion showed larger zones (21.00 ± 1.00 mm at 500 µg/mL; 25.00 ± 1.00 mm at 530 µg/mL; p < 0.01).
Conclusion: P. acidilactici postbiotics demonstrate promising antimicrobial activity against P. aeruginosa, supporting their potential as alternative therapeutics. Further research is needed to explore mechanisms and clinical applications.

Key words: Antimicrobial activity, Postbiotic, Probiotic, Pseudomonas aeruginosa, Pediococcus acidilactici