Probiotic potential of Lactobacilli with antagonistic activity against pathogenic strains: An in vitro validation for the production of inhibitory substances

Abstract

BackgroundProbiotics, live cells with different beneficiary characteristics, have been extensively studied and explored commercially in many different products in the world. Their benefits to human and animal health have proven in hundreds of scientific studies. Based on rich bibliographic material, Curd is the potential source of probiotic Lactobacilli.MethodThe aim of the present study was to observe Lactobacilli with probiotic potential activities from different curd samples for isolation, identification and characterization of Lactobacillus species.ResultsAmong the samples, thirty lactic acid bacterial strains were isolated, sixteen (16/30) best Lactobacillus isolates were selected by preliminary screening as potential probiotic for acid and bile tolerance, further confirmed using 16s rRNA identification. All the selected Lactobacillus isolates were then characterized in vitro for their probiotic characteristics and antimicrobial activities against pathogens and aggregation studies. The results indicated that selected potential probiotic isolates (T2, T4 and T16) were screened and confirmed as Lactobacillus. The isolates produced positive tolerance to excited pH, NaCl and bile salts, also revealed noticeable antimicrobial activities against pathogens. All the Lactobacillus isolates were susceptible to clinical antibiotics used. Besides, T2 isolate was constituted to retain stronger auto and co-aggregation and cell surface hydrophobicity capacity.ConclusionBased on the drawn results, T2, T4 and T16 Lactobacillus isolates were recognised as ideal, potential in vitro antimicrobial probiotic isolates against pathogens and studies are needed further in-vivo assessment and human health benefits in their real-life situations.

Antimicrobial activity ofLactobacillus rhamnosusagainstPseudomonas fluorescensandPseudomonas putidafrom raw milk

“…The mean values of the diameters of zone inhibitions were 1.9 cm for P. fluorescens and 1.6 cm for P. putida (Figure a and b), similarly to Prabhurajeshwar and Chandrakanth () that isolated Lactobacillus spp. from curd, assessed the production of antimicrobial compounds (bacteriocins and organic acids) and evaluated the antagonistic actions against pathogenic agents such as P. aeruginosa .…”

“…Lactic acid bacteria (LAB) exert inhibitory effects against the growth of deteriorating and pathogenic microorganisms through the production of antimicrobial compounds (Coman et al, ; Prabhurajeshwar & Chandrakanth, ; Wang, Chang, Yang, & Cui, ). According to Todorov and Dicks (), Lactobacillus rhamnosus is found in diverse habitats, and its inhibitory action is a result of the combined effects of bacteriocins, organic acids, and hydrogen peroxide.…”

Assessing inhibitory activity of probiotic culture supernatants against Pseudomonas aeruginosa: a comparative methodology between agar diffusion, broth culture and microcalorimetry

“…The final CFU/mL of P. aeruginosa in all three CFS therefore did not show any difference which emphases the fact that the broth culture method is limited by multiple sampling and concomitant plating to determine these effects unlike the IMC which records real-time metabolism of the microorganisms Agar diffusion assay is the most commonly used method to determine antimicrobial activity of bacteria and bacteriocin activity (Masoumikia and Ganbarov 2015;Prabhurajeshwar and Chandrakanth 2017;Sukhina et al 2012). However, this method is dependent on the inhibitory compound diffusing through the agar which could be affected by size, medium components and other molecules secreted by the bacteria which could possibly react (Arena et al 2016).…”

Specific composition of indigenous microflora (Lactobacillus spp., Bifidobacterium spp., Lactococcus spp.) in farm animals

“…According to the cultural and morphological features, the cultures of bifidobacteria we have allocated were attributed to B. adolescentis, B. infantis B. bifidum, B. breve, B. lactentis, B. longum, and B. suis. According to existing data, lactococci belong to the group of gram-positive cocci (Neville et al, 2012;Prabhurajeshwar & Chandrakanth, 2017). Bacteria have cells of spherical or oval shape, 0.5-1.2 x 0.5-1.5 microns in size, grow in pairs and short chains in liquid medium, do not form endospores, gram-positive, no motile, have no capsules.…”