Comparative Genomic and Phenotypic Analysis of the Vaginal Probiotic GR-1.

represents a versatile bacterial genus, which can adapt to a wide variety of ecological niches, including human body sites such as the intestinal and urogenital tract. In this study, the complete genome sequence of the vaginal probiotic GR-1 was determined and compared to other strains at genomic and phenotypic level. The strain GR-1 was originally isolated from a female urethra, and was assessed with GG from a feces sample of a healthy male, and LC705 from a dairy product. A key difference is the absence in GR-1 and LC705 of the locus required for pili-mediated intestinal epithelial adhesion. In addition, the GR-1 genome contains a unique cluster for exopolysaccharide production, which is postulated to synthesize glucose-rich, rhamnose-lacking exopolysaccharide molecules that are different from the galactose-rich extracellular polysaccharide of GG. Compared to GG, GR-1 was also genetically predicted and experimentally shown to better metabolize lactose and maltose, and to better withstand oxidative stress, which is of relevance in the vagina. This study could thus provide a molecular framework for the selection of the optimal probiotic strain for each targeted niche and condition, but further substantiation of niche adaptation mechanisms of lactobacilli is warranted.