بررسی اثر ضد میکروبی نایسین بر روی باکتریهای استافیلوکوکوس اورئوس و باسیلوس سرئوس

Title

Evaloution of Antimicrobial Effects of Nisin on Staphylococcus aureus and Bacillus cereus Bacteria by Disc Diffusion Methods

English Abstract

Background & Objectives: Lantibiotics agents produced by lactic acid bacteria are a branch of Bactericins.Nisin, composed from34 amino acids, belongs to Lantibiotics peptidefamily, which including modifiedLantionin and methyl Lantionin as modified amino acids andused as preservative food agent. Gram positive bacteria including Staphylococcus aureus and Bacillus cereus bacteria are cause food poisoning.In this study the antimicrobial effect of nisin on model gram positive bacteria has been investigated. Methods: Nisin solution was obtained by dissolving 1 mg of nisin in HCl 0.02 N and adjusting via DDW to 1mg.ml-1. Staphylococcus aureus and Bacillus cereus bacteria were grown in Mueller Hinton Broth and were cultured on Mueller Hinton agar mediumafter arriving to half McFarland turbidity. Antibiogram blank discs were placed on thebacterial inoculated plate and 10 microliters of freshnisin stock solution added per disc. Then bacteria were incubatedat 35 °C overnight. Results: After overnight incubation created clear zone around each disc were observed in a triplicate manner, i.e. lack of bacterial colonies were confirmed in the zone. This clear zone indicates antimicrobial activity of nisin against the Staphylococcus aureus and Bacillus cereus. Conclusion: Nisinantimicrobial activity against model gram positive, Staphylococcus aureus and Bacillus cereus, bacteria confirmed at 1mg.ml-1 concentration. Results altogether showed that although nisin lantibiotic peptide has potential antimicrobial property and could be a candidatefor medical applications and food industry and peptide drug delivery aims, however more studies yet needed in this area.

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