Effects Of Protein-Rich Fraction From Lactobacillus Plantarum Usm8613 Against Dermal Staphylococcus Aureus
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Date
2016-07
Authors
Yong, Cheng Chung
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Abstract
Thirty-six strains of lactic acid bacteria were isolated from local dairy, meat and fermented products. Cell-free-supernatant (CFS) of L. plantarum USM8613, isolated from fermented sausage, was selected for subsequent analyses. The CFS exhibited a significantly stronger (ρ < 0.05) inhibitory activity against S. aureus and produced a higher amount of lactic acid as compared to all strains studied. Ex-vivo study demonstrated CFS from L. plantarum USM8613 inhibited the growth and biofilm formation of S. aureus on porcine skins. CFS of L. plantarum USM8613 was fractionated into protein-rich, lipid-rich and polysaccharide-rich fractions, and all fractions exhibited significant inhibitory activity, with a more prevalent effect from the protein-rich fraction. The antimicrobial and anti-biofilm effects of the protein-rich fraction were further confirmed with S. aureus-infected porcine skins. Topical application of ointment containing 800 AU/mL of the protein-rich fraction from L. plantarum USM8613 significantly reduced (ρ < 0.05) the cell counts of S. aureus in the wound site of S. aureus infected-rats. The production of IL-4, IL-6, IFN-Ɣ, TGF-β and TNF-α, and the expression of matrix metalloproteinases (MMPs) and β-defensin were also significantly elevated (ρ < 0.05) upon treatment with the protein-rich fraction. Altogether, it indicated that the protein-rich faction promoted wound healing by regulating the immune effectors involved in wound healing. Gene expression study of S. aureus showed the stress regulator gene (sigB) and the major autolysin gene (atl) were significantly up-regulated upon treatment with the protein-rich fraction and contributed
to the autolysis and cell death of S. aureus itself. Pathogenicity factors of S. aureus (hla, hlb, spaV genes) were also suppressed upon the protein-rich fraction treatment. The use of atl null mutant strain of S. aureus, which further justified the inhibitory effect of the protein-rich fraction from L. plantarum USM8613, was achieved via up-regulation of the major autolysin, atl gene. Genome-wide analysis revealed a genome size of 3,258,106 bp of L. plantarum USM8613, demonstrating the adaption of L. plantarum USM8613 to utilise a large variety of carbon and amino acid sources from the surroundings for survival. The genome of L. plantarum USM8613 contained all five plantaricin operons and the functionality of these operons was confirmed via gene expression analysis. Altogether, results in this research demonstrated the protein-rich fraction from L. plantarum USM8613 effectively inhibited the growth and suppressed the pathogenicity of S. aureus, and promoted wound healing. Therefore, the protein-rich fraction from L. plantarum USM8613 could be applied as a bioactive agent in the dermatological industry for the treatment of S. aureus infection and wound healing.
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Effects of protein-rich fraction from lactobacillus plantarum , against dermal staphylococcus aureus.