Potential probiotic characterization of strains isolated from gut microbiota of Chinese young adults

The human gut microbiota affects a variety of biochemical and metabolic functions of the human system directly or indirectly. The geographical location seems to explain the microbial variation, significantly influencing the diversity, stability and relative abundance of the numerous bacterial species. Differences in the composition of the gut microbiota in different populations are also based on diet and lifestyle changes, and among the many variables, diets and geographic locations often overlap. Chinese diet is dominated by grains, rice, and flour. Red meat and vegetable oils are usually consumed in large quantities, accompanied by vegetables and fruits, which together constitute the daily diet. Chinese young adults were enrolled in a parallel study investigating the plasticity of gut microbiota in environmental/dietary changes due to mobility from China to Italy. The original diet of the subjects was rich in prebiotics, such as mushrooms typical of North-East of China. Novel bacterial strains have been isolated from stool samples of the young subjects, identified by MALDI-TOF and 16S rDNA gene sequencing. The isolated strains have been screened for their potential probiotic properties applying a series of tests, such as tolerance to low pH and bile acids, antimicrobial activity, resistance to antibiotics, adherence on intestinal cells. Moreover, the activity of bioactive components of the cell free supernatants and their effect on pathogens have been assessed. All these properties are expected for screening promising probiotic strains showing some peculiar characteristics. Putative new probiotic strains of lactobacilli and of the recently emerging Weissella cibaria were isolated and characterized to be finally validated on animal models as dietary supplements or functional food ingredients with highly positive impact on the human health.