Characterization of Lactobacillus strains isolated from Algerian children faeces for their probiotic properties

Abstract

Lactic acid bacteria termed probiotics have preventive as well as curative effects on several types of diarrhoea of different aetiologies. The main objective of this study was to screen lactobacilli strains having probiotic traits, isolated from Algerian healthy children faeces on the purpose of using them further in children diarrheal illnesses. One hundred and twenty (120) lactic acid bacteria isolates were selected from faecal samples of healthy Algerian children aged between five and ten years. Gram positive rods and catalase negative bacteria (52 isolates) were screened, in vitro, for their probiotic potential properties including ability to survive in simulated gastro-intestinal conditions, adherence to Caco-2 cells and their antimicrobial activity. The results show that only five strains resisted in simulated gastric juice at pH 1.5 and pepsin. Four of them were resistant to simulated intestinal conditions at pH 8 and pancreatin and have a good adherence. In the end, three of them were retained as they display interesting probiotic profiles characterized by a strong antimicrobial effect against some intestinal pathogenic bacteria. They were identified by 16S rDNA sequencing as Lactobacillus plantarum F12, Lactobacillus brevis G6 and Lactobacillus paracasei B13.

Antibacterial effects of Lactobacillus isolates of curd and human milk origin against food-borne and human pathogens

“…In contrary, perusal of data in Table 2 revealed that CFSs of lactobacilli exhibited moderate-to-good antagonistic activity against B. cereus . Similar to our results, high antagonistic activity against B. cereus was reported by other researchers (Bahri et al 2014; Mahasneh et al 2015) as well. CFSs of lactobacilli displayed varied antibacterial activities, and this could be attributed to the secretion of different antimicrobial substances or metabolites such as organic acids (lactic and acetic acids), hydrogen peroxide, ethanol, diacetyl, bacteriocins, peptides etc.…”

“…Interestingly, CFSs of most of our isolates displayed antagonistic activity against Salmonella enterica serovar Typhi. Abdel-Daim et al (2013) and Bahri et al (2014) also reported strong-to-weak inhibitory activity of Lactobacillus supernatants against Salmonella spp. Besides, we have also observed the antagonistic activity of Lactobacillus CFSs against P. aeruginosa , one of the alarming opportunistic pathogen in hospitalized, immuno-compromised, and cystic fibrosis patients.…”

Isolation of Lactobacillus strain from curdled milk and investigation of their antimycotoxinogen activity

“…The cell appears rod shaped, immobile, and Grampositive. These results corroborate those obtained by Hoque et al (2010); and Bahri et al (2014) attesting that this strain belongs to Lactobacillus genus. In addition, Mannan, Refaya Rezwan, Rahman, and Begum (2017), reported in their study that, 25 bacteria were isolated from yogurt and cheese samples in Dhaka Metropolitan Area and identified as Lactobacillus species by morphological and short biochemical tests.…”

“…Researchers have developed that LAB can be used for food fermentation, for probiotic effects and for food preservation (Ahmad Rather et al, 2013;Bahri et al, 2014;Biernasiak, Piotrowska, & Libudzisz, 2006). Their preventing effect against some toxinogenic fungi is through some mechanisms, including production of organic acids, hydrogen peroxide, fatty acids, caproic acid (Corsetti, Gobetti, Rossi, & Damiani, 1998), synergic antifungal metabolite like phenyl lactic acid, 3-hydroxylated fatty acids (Strom, Sjogren, Broberg, & Schnurer, 2002), cyclic dipeptides (Li, Liu, Zhang, Cui, & Lv, 2012) and other antimicrobial compounds, such as bacteriocins (Temmerman, Pot, Huys, & Swings, 2003;Mokoena, 2017).…”