Postbiotic effect evaluation of Lactobacillus acidophilus and Lactobacillus plantarum 299v lysates obtained through ultrasonication against common skin pathogenic bacteria

Abstract

The skin microbiome refers to the community of microorganisms that reside on the human skin. There’s an important equilibrium and protection relationship among these microorganisms and the skin that is achieved through metabolite production, immunomodulation and colonization. Microbiota alterations result in dysbiosis, an imbalance in the microbial communities that is associated with the development of cutaneous diseases such as acne vulgaris, atopic dermatitis and impetigo. To recover the skin equilibrium, probiotic bacteria and postbiotic use are attractive approaches because of their role in disease modulation through possible elimination of pathogenic bacteria. Since postbiotics are molecules such as enzymes, proteins and soluble factors produced or released by the probiotic bacteria metabolism, there is less associated risk in comparison with administrating live bacteria through exogenous applications. The objective of this study is to evaluate the antimicrobial effects of postbiotics obtained from L. acidophilus and L. plantarum 299v lysates against the common skin pathogens Cutibacterium acnes, Staphylococcus aureus and Streptococcus pyogenes. Lysates were obtained through ultrasonication (US) alone or a combination and freeze-thawing and US (FT+US). Antimicrobial activity of lysates, supernatants, non-lysed and heat-killed cells was evaluated by the agar well diffusion method and total protein of the lysates was quantified using the Bicinchoninic Acid assay. In this work, results confirm the significant antimicrobial activity of the ultrasonicated lysates of L. acidophilus against S. aureus and C. acnes, while L. plantarum 299 lysates only showed an effect against C. acnes. Also, the presence of acids is directly correlated with the formation of inhibition zones for L. plantarum 299v pH 3.8 supernatant. Lysates result in a complete loss of antimicrobial activity after heating at 80°C for 1.5 h, which suggests a possible denaturalization of antimicrobial peptides. It is concluded L. acidophilus and L. plantarum 299v postbiotics obtained through cellular lysis using sonication present a strain dependent antimicrobial effect that could be applied to prevent skin diseases such as acne vulgaris and atopic dermatitis.