Characterization of lactobacilli strains isolated from baby’s feces for their potential immunobiotic application

Abstract

Background and Objectives: Several LAB species were evaluated and characterized for potential probiotic use. Besides the antimicrobial activity, probiotics showed recently a capacity to prevent and to alleviate inflammatory and chronic diseases. Immunomodulation effect is one of the modes of actions of such probiotics, called immunobiotics, which can be used in several chronic diseases such as Inflammatory Bowel Diseases (IBD). The aim of this study was to isolate, identify and characterize lactobacilli strains from healthy baby’s feces in order to select some strains with potential immunobiotic application especially strains which can stimulate anti-inflammatory responses. Materials and Methods: Forty-two LAB strains were isolated and identified by the MALDI-TOF / MS technique. In addition, strains were subjected to several assessments such as antimicrobial activity, the capacity to form biofilm in polystyrene microplate and immunomodulation activity in a PBMC model. Results: Results showed that the majority of strains (90.4%) were identified as Lactobacillus. However, among these, only 39.4% of lactobacilli strains were not identified at the species level. All isolated lactobacilli strains showed an anti-inflammatory effect. Moreover, 7 strains were considered as good probiotic candidates based on their characteristics such as their antibacterial activities, formation of the strongest biofilm and their ability to stimulate an anti-inflammatory response in PBMCs model. Conclusion: Two strains (Lactobacillus spp S14 and Lactobacillus spp S49) which showed the best immunobiotic characteristics, could be selected and evaluated more deeply in vivo model as well as in human clinical study to ensure their effectiveness in inflammatory diseases such as IBD.

Keywords

• Lactobacilli; Immunomodulation; Immunobiotic; Probiotic; Inflammatory bowel disease