Influence of manufacturing processes on in vitro properties of the probiotic strain Lactobacillus rhamnosus Lcr35®

Probiotics are administered as complex manufactured products and yet most studies on probiotic bacterial strains have been performed with native culture strains. Little is known about the influence of industrial processes on the properties of the microorganisms. In this study, we comparatively assessed the characteristics of the probiotic bacterial strain Lactobacillus rhamnosus (Lcr35®) together with four of its commercial formulations, including three intestinal formulas (BACILOR with Lcr Restituo® packet and capsule and FLOREA Lcr Lenio®) and one vaginal formula (GYNOPHILUS Lcr Regenerans®). Lcr35® grown from the intestinal formulas displayed increased resistance to acidic pH and bile stress, especially FLOREA (Lcr Lenio®), which showed a 4.5 log higher number of viable bacteria compared to the results obtained with the control native Lcr35® strain. Adhesion to intestinal cells was significantly higher with Lcr Restituo® packet and Lcr Restituo® capsule vs Lcr35®. Bacteria from the vaginal formulation GYNOPHILUS had increased ability to metabolize glycogen thereby increasing lactic acid production. In vitro growth inhibition of the pathogen Candida albicans was significantly higher with bacteria from the vaginal formulation (4.5 log difference) and in the presence of vaginal epithelial cells than with the native strain. Our results show that the manufacturing process influences strain properties and should therefore be adapted according to the strain and the therapeutic indication.

► The probiotic properties of microorganisms are usually determined on native culture strains.
► The aim of this study was to show that the strains characterization was a first step but not enough to evaluate the finished products.
► In vitro studies must be also applied on the active pharmaceutical ingredient (API).
► The strain Lactobacillus rhamnosus Lcr35® included in different products show different specifications adapted to therapeutic target.