This study aims to evaluate the effects of bioactive metabolites produced by lactic acid bacteria against methicillin-resistant Staphylococcus aureus (MRSA) ATCC 43300. A total of six lactic acid bacteria (LAB) were selected to evaluate the antimicrobial activity against MRSA ATCC 43300, a skin pathogen that is highly resistant to most antibiotics. The K014 isolate from a fermented vegetable recorded the highest inhibition against MRSA ATCC 43300 at 91.93 ± 0.36%. 16S rRNA sequencing revealed the K014 isolate is closely related to L. plantarum and the sequence was subsequently deposited in the GenBank database with an accession number of MW180960, named as Lactiplantibacillus plantarum K014. The cell-free supernatant (CFS) of L. plantarum K014 had tolerance to high temperature as well as acidic pH. The bioactive metabolites, such as hydrogen peroxide, lactic acid and hyaluronic acid, were produced by L. plantarum K014. Result from ABTS assay showed higher antioxidant activity (46.28%) as compared to that obtained by DPPH assay (2.97%). The CFS had showed anti-inflammatory activity for lipoxygenase (LOX) assay at 43.66%. The bioactive metabolites of L. plantarum K014 showed very promising potential to be used topical skin pathogens.
Fresh raw shrimps were dipped for 10, 20, and 30 min at room temperature (25°C ± 1°C) in lactic acid (LA; 1.5%, 3.0%, v/v) to evaluate their antipathogenic effects against Vibrio cholerae, Vibrio parahaemolyticus, Salmonella entreitidis, and Escherichia coli O157:H7 inoculated at a level of 10(5) CFU/g. Significant reductions in the population of all these pathogenic bacteria were recorded after dipping treatments, which were correlated to the corresponding LA concentrations and treatment time. With respect to the microbial quality, 3.0% LA treatment for 10 min was acceptable in reducing the pathogenic bacteria. Additionally, sensory evaluation results revealed a 10-min dip in 3.0% LA to be more acceptable organoleptically compared with 20 and 30 min of treatments. Results of the present study are envisaged to be useful for commercial applications for effective decontamination of shrimp.
Probiotics have been extensively reviewed for decades, emphasizing on improving general gut health. Recently, more studies showed that probiotics may exert other health-promoting effects beyond gut well-being, attributed to the rise of the gut-brain axis correlations. Some of these new benefits include skin health such as improving atopic eczema, atopic dermatitis, healing of burn and scars, skin-rejuvenating properties and improving skin innate immunity. Increasing evidence has also showed that bacterial compounds such as cell wall fragments, their metabolites and dead bacteria can elicit certain immune responses on the skin and improve skin barrier functions. This review aimed to underline the mechanisms or the exact compounds underlying the benefits of bacterial extract on the skin based on evidences from in vivo and in vitro studies. This review could be of help in screening of probiotic strains with potential dermal enhancing properties for topical applications.
The objective was to screen and evaluate the anti-fungal activity of lactic acid bacteria (LABs) isolated from Malaysian fermented foods against two Trichophyton species. A total of 66 LAB strains were screened using dual culture assays. This showed that four LAB strains were very effective in inhibiting growth of T. rubrum but not T. interdigitale. More detailed studies with Lactobacillus plantarum strain HT-W104-B1 showed that the supernatant was mainly responsible for inhibiting the growth of T. rubrum. The minimum inhibitory concentration (MIC), inhibitory concentration, the 50% growth inhibition (IC50) and minimum fungicide concentration (MFC) were 20 mg/mL, 14 mg/mL and 30 mg/mL, respectively. A total of six metabolites were found in the supernatant, with the two major metabolites being L-lactic acid (19.1 mg/g cell dry weight (CDW)) and acetic acid (2.2 mg/g CDW). A comparative study on keratin agar media showed that the natural mixture in the supernatants predominantly contained L-lactic and acetic acid, and this significantly controlled the growth of T. rubrum. The pure two individual compounds were less effective. Potential exists for application of the natural mixture of compounds for the treatment of skin infection by T. rubrum.
The purification of human adipose-derived stem cells (hADSCs) from human adipose tissue cells (stromal vascular fraction) was investigated using membrane filtration through poly(lactide-co-glycolic acid)/silk screen hybrid membranes. Membrane filtration methods are attractive in regenerative medicine because they reduce the time required to purify hADSCs (i.e., less than 30 min) compared with conventional culture methods, which require 5-12 days. hADSCs expressing the mesenchymal stem cell markers CD44, CD73, and CD90 were concentrated in the permeation solution from the hybrid membranes. Expression of the surface markers CD44, CD73, and CD99 on the cells in the permeation solution from the hybrid membranes, which were obtained using 18 mL of feed solution containing 50 × 10⁴ cells, was statistically significantly higher than that of the primary adipose tissue cells, indicating that the hADSCs can be purified in the permeation solution by the membrane filtration method. Cells expressing the stem cell-associated marker CD34 could be successfully isolated in the permeation solution, whereas CD34⁺ cells could not be purified by the conventional culture method. The hADSCs in the permeation solution demonstrated a superior capacity for osteogenic differentiation based on their alkali phosphatase activity, their osterix gene expression, and the results of mineralization analysis by Alizarin Red S and von Kossa staining compared with the cells from the suspension of human adipose tissue. These results suggest that the hADSCs capable of osteogenic differentiation preferentially permeate through the hybrid membranes.