Lactobacillus rhamnosus GR-1 and L. fermentum RC-14, previously characterized as urogenital probiotics were evaluated for human intestinal applications. RC-14 and GR-1 were tolerant to 0.3 and 0.5% (w/v) bile, respectively. Both strains were suspended in skim milk, stored as a frozen concentrate and administered in combination to five healthy women twice daily for 14 days. Faecal samples were analyzed and the Lactobacillus flora assessed by Randomly Amplified Polymorphic DNA (RAPD). Both strains were recovered from all subjects during the 14-day administration period and GR-1 was detected for at least 7 days post-administration in some individuals. No notable increases in serum IgG, IgA or IgM were observed and IL-2 and IL-4 were undetectable. Although IL-6 and IFN-γ levels increased slightly in some individuals, concentrations remained within normal ranges. Thus, L. rhamnosus GR-1 and L. fermentum RC-14 are bile tolerant and survive gastrointestinal transit without induction of systemic immune or inflammatory responses. These data together with the previously demonstrated probiotic properties of GR-1 and RC-14 make this strain combination potentially useful for human intestinal applications.
- Gastrointestinal tract