The vaginal isolate Lactobacillus paracasei LPC-S01 (DSM 26760) is suitable for oral administration

Abstract

Bacterial vaginosis is one of the most common urogenital diseases affecting women in reproductive age. The administration of probiotics as vaginal suppository has been proposed as a strategy to cure this condition and reduce its recurrence. Nonetheless, also oral consumption of probiotics, which is a more practical route of administration, proved to be an efficient strategy. In this perspective, we studied Lactobacillus paracasei LPC-S01 (DSM 26760), a human vaginal isolate included in commercial probiotic preparations for topical use, in order to assess if this bacterium can also perform as gastrointestinal probiotic. Comparative genomics revealed the presence of several accessory genes suggesting that LPC-S01 is a niche-generalist member of its species. According to a procedure conventionally used to predict the probiotic potential, we demonstrated that the probiotic properties of strain LPC-S01, with respect to those of the well-known probiotic references L. paracasei Shirota and DG, are equal for the bile tolerance and the reduction of NF-κB activation in Caco-2 cells, or superior for the tolerance to gastric juice and the adhesion to Caco-2 epithelial cells. We then demonstrated that LPC-S01 is susceptible to antibiotics indicated by EFSA and does not produce biogenic amines. Finally, a double-blind cross-over pilot intervention trial on healthy human volunteers showed that, after a 7-days oral consumption of capsules containing about 24 billion live cells, the fecal cell concentrations of strains LPC-S01 and DG (evaluated by qPCR) were not dissimilar. Specifically, both probiotics' cell concentrations were above the detection limit for an average of 5 days from the end of the treatment, corresponding to a mean number of evacuations of 7 ± 2. Taken together, these data demonstrate that the vaginal isolate L. paracasei LPC-S01 possesses safety and functional properties that may support its use as probiotic to be administered per os for potential intestinal as well as vaginal applications.

A Novel Rhamnose-Rich Hetero-exopolysaccharide Isolated from Lactobacillus paracasei DG Activates THP-1 Human Monocytic Cells

“…Nonetheless, in our experiments, purified EPS was unable to affect the adhesion properties of strain DG. In fact, the adhesion of L. paracasei DG was not significantly different from that of nDG and was quite modest (about 300 bacteria per 100 Caco-2 cells), as reported previously (14); in addition, adhesion ability was not affected by coincubation of the bacterial cells with purified EPS (data not shown).…”

“…Stirring a suspension of the cells overnight in an aqueous solution of sodium hydroxide (1 M) and then precipitating crude polysaccharide by adding 2 volumes of ethanol yielded a significant amount of material, which included both polysaccharide and protein. The same approach was adopted for the isolation of extracellular polysaccharide molecules from strain L. paracasei LPC-S01, whose genome has been reported to harbor two distinct putative EPS operons (14), one of which is identical to strain DG EPS-a. However, we failed to obtain significant amounts of EPS from LPC-S01.…”

“…In a previous publication, L. paracasei DG was shown to be moderately adhesive on a Caco-2 cell layer (14). In this study, the potential involvement of DG-EPS was assessed by testing the adhesion ability of strain DG after the removal of the EPS molecule ("naked" DG cells [nDG], prepared by phosphate-buffered saline [PBS] washes and mild sonication) and upon preincubation of Caco-2 cells with purified EPS.…”

“…We recently showed that L. paracasei DG possesses an evident ability to reduce NF-B activation in Caco-2 cells at baseline and upon stimulation with the proinflammatory cytokine interleukin 1␤ (IL-1␤) (14), as determined through a reporter system obtained by transfecting Caco-2 cells with a luciferase reporter vector (6, 7). Here we used the same immunological model to test the EPS macromolecule isolated from strain DG.…”

“…The dry mass of EPS was then determined. The EPS preparations were tested for the presence of contaminating bacterial DNA through real-time quantitative PCR (q-PCR) with two primer pairs: universal primers targeting the 16S rRNA gene (EUB) and DG strain-specific primers targeting the welF gene (14). This analysis revealed the presence of 10 to 63 ng ml Ϫ1 in the 1-mg ml Ϫ1 stock solutions of EPS, corresponding to an overall maximum concentration of 0.6 ng ml Ϫ1 of DNA incubated with THP-1 cells when the highest concentration of EPS (10 g ml Ϫ1 ) was used in immunological experiments.…”