Antagonistic Activity of Bacteriocin- Producing Lactobacillus local isolates against some pathogenic bacterial species

Background and Objective: Lactobacilli are known for their probiotic activities and potential to combat pathogens. This study aimed to investigate the antimicrobial activity of Lactobacillus strains isolated from various sources against pathogenic bacteria, with the objective of identifying potential bacteriocin producers. Methods: A total of 140 samples were collected from different sources. Lactobacillus spp. were isolated from these samples and cultured on MRS agar medium under anaerobic conditions. The suspected colonies were characterized, and the bacterial cells appeared Gram positive, diploid bacilli or coccobacilli. The isolates were subjected to various biochemical tests and identified using the Vitek2 automated system. The antimicrobial activity of bacteriocin was screened through primary and secondary techniques, with the agar well diffusion method proving the most effective. Molecular identification of the best bacteriocin producer was achieved using 16S rRNA sequencing. Results: The study found that L. helveticus DF isolated from feces exhibited the highest bacteriocin production efficiency. Concentrated bacteriocin from L. helveticus DF demonstrated potent antibacterial activity, with 80 AU/ml against Pseudomonas aeruginosa and 40 AU/ml against Enterococcus faecalis, the most sensitive bacterial isolates. These findings suggest the potential of Lactobacillus bacteriocins as effective antibacterial agents, offering an alternative approach to address antibiotic resistance. Conclusion: The study highlights the potential of Lactobacillus bacteriocins as effective antibacterial agents, offering a promising alternative to combat antibiotic resistance. Further research is warranted to elucidate the mechanisms and assess the safety and efficacy of bacteriocins for their use as bio-therapeutic agents.