Safety and Probiotics Evaluation of Bifidobacterial Genomes Isolated from Probiotic Products.

Bifidobacterium is a common bacterium colonizing human intestines which is frequently used to produce probiotic-related products. Since the rapid development of probiotic products field over recent years, improving probiotic-related testing methods, as well as conducting systematic safety evaluations is urgently needed. Advances in sequencing technology enable clinicians to access the complete genome of bacteria more effectively via whole genome sequencing, thereby providing a solution for the safety evaluation of probiotics. In our current study, seven samples of the Bifidobacterium spp. were isolated from probiotic products, and genomic analysis were used to improve the identification of Bifidobacterium spp. at the species and subspecies levels. Notably, the obtained high-quality complete genomes were employed to predict the genetically encoded drug resistance and virulence attributes of seven Bifidobacterium strains, which further improve the evaluation of probiotics safety. Genes imparting beneficial functional properties, as well as those associated with colonization and survival within the gastrointestinal tract were presented in all strains. In addition, whole genome sequencing-based analysis combined with phylogenetic trees could help identify the subspecies and facilitate the analysis of the existing homology of samples and the previously reported differences between strains. Our study evaluated the accuracy of mainstream approaches in identifying the bacteria probiotic-related products, and uncovered the deceptive facts in bacteria labeling. Our findings could provide the experimental basis for subspecies level bacterial identification in probiotic-related industry, and to help establish a standard systematic safety evaluation method.