Isolment et caracterisation des souches de lactobacilles a caracteres probiotiques a partir de selles d’enfants

Abstract

"In this study, 120 strains of lactic acid bacteria were isolated from Algerian children faeces. The phenotypic identification by morphological and biochemical tests showed that fifty two strains belonged to the genus Lactobacillus. The identification by API 50 CH led to different species as : L. fermentum (10 strains), L. casei (8 strains), L. gasseri (8 strains), L. salivarius (5 strains), L. plantarum (5 strains ), L. vaginalis (4 strains), L. paracasei sp (4 strains), L. brevis (2 strains), L. reuteri (2 strains), L. acidophilus (2 strains) et L. ruminis (2 strains). The probiotic profile of lactobacilli strains was examined, in vitro, in a purpose of possible use in children infectious diarrhoea. To do this, we were interested to evaluate their ability to survive in gastric and intestinal simulated conditions, the adherence to human epithelial cells Caco-2 and the antibacterial activity against a range of enteropathogenic bacteria. Their safety aspect was also examined by hemolytic activity and antibiotic resistance. At the end three strains, with high probiotic profile characterized by a strong antibacterial activity, were selected. In addition, the study of their security aspect revealed that were non hemolytic and free of acquired resistance against tested antibiotics which reinforces their choice as ""safe"" probiotics for possible use in the fight and control of children infectious diarrhea. The identification of screened probiotic bacteria was confirmed by DNAr 16S sequencing as L. paracasei (B13), L. brevis (G6) and L. plantarum (F12). They were deposited in the GenBank."