Lactobacillus plantarum strain HT-W104-B1: potential bacterium isolated from Malaysian fermented foods for control of the dermatophyte Trichophyton rubrum

Abstract

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.

Antifungal activity of probiotic strain Lactiplantibacillus plantarum MYSN7 against Trichophyton tonsurans

“…Previously, L. plantarum has been shown to produce organic acids, such as phenyl lactic acid (Maikhan and Researcher, 2018 ), benzene acetic acid, 2-propenyl ester (Wang et al, 2012 ), oleic acid (Rao et al, 2019 ), 10-octadecenoic acid, palmitic acid, heptadecanoic acid, stearic acid, and lauric acid (Deepthi et al, 2016 ). Nevertheless, the antifungal effect seemed to be maximal with the use of a mixture of organic acids rather than any single acid (Danial et al, 2021 ).…”

“…Each LAB strain was maintained in glycerol stock. To obtain the cell-free supernatant (CFS), 300 µl of LAB cell suspension (10 6 CFU/ml) was inoculated in 30 ml of MRS broth and incubated at 37 • C for 48 h. The CFS was obtained by centrifuging the broth at 3,000 rpm for 15 min at 4 • C. It was then sterilized by filtration using a 0.2-µm syringe filter (AXIVA) and freeze-dried aseptically (Danial et al, 2021).…”

“…One of the ideal sources to look for probiotics to fight against indigenous fungal pathogens is the traditional fermented foods prepared locally and have been in use for generations. Different Lactiplantibacillus spp isolated from such fermented foods have been examined with success for their antifungal activity (Arena et al, 2018 ) Although one of the best-known probiotic species, Lactiplantibacillus plantarum , has been explored for its antifungal activity against Aspergillus spp (Bukhari et al, 2020 ), Penicillium spp (Wang et al, 2012 ), Fusarium proliferatum (Deepthi et al, 2016 ), and T. rubrum (Danial et al, 2021 ), its effect on Trichophyton tonsurans is yet to be investigated.…”