Development of omics‐based protocols for the microbiological characterization of multi‐strain formulations marketed as probiotics: the case of VSL#3

Abstract

Summary The growing commercial interest in multi‐strain formulations marketed as probiotics has not been accompanied by an equal increase in the evaluation of quality levels of these biotechnological products. The multi‐strain product VSL#3 was used as a model to setup a microbiological characterization that could be extended to other formulations with high complexity. Shotgun metagenomics by deep Illumina sequencing was applied to DNA isolated from the commercial VSL#3 product to confirm strains identity safety and composition. Single‐cell analysis was used to evaluate the cell viability, and β‐galactosidase and urease activity have been used as marker to monitor the reproducibility of the production process. Similarly, these lots were characterized in detail by a metaproteomics approach for which a robust protein extraction protocol was combined with advanced mass spectrometry. The results identified over 1600 protein groups belonging to all strains present in the VSL#3 formulation. Of interest, only 3.2 % proteins showed significant differences mainly related to small variations in strain abundance. The protocols developed in this study addressed several quality criteria that are relevant for marketed multi‐strain products and these represent the first efforts to define the quality of complex probiotic formulations such as VSL#3.

Global analysis of clinical trials with probiotics

“…lactis BB12 ( Jungersen et al., 2014 ) with 55 studies. VSL#3, a consortium of 3 different bifidobacteria, 4 lactobacilli, and 1 Streptococcus thermophilus strain ( Mora et al., 2019 ), was the most registered multispecies preparation in 74 studies (see also below).…”

Bulk and Surface Wettability Characteristics of Probiotic Powders in Their Compressed Disc and Packed-Bed Column Forms

“… 8 There, the contact angle was immediately determined after drop deposition and a probiotic lawn was prepared on a porous filter support from a known amount of particle dispersion preparation. 22 As the majority of strains of such a multistrain probiotic powder are constituted by Streptococcus thermophilus (>60% of total strains), 23 such a result would be expected owing to the high surface affinity for water of this bacterial species, besides the presence of a hydrophilic anticake agent SiO 2 in the powder. The sessile drop method combined with the compressed disc preparation under the same defined pressure (3850 bar) provides reproducible data and appears as a very practical tool for probiotic characterizations.…”

Impact of a Multistrain Probiotic Formulation with High Bifidobacterial Content on the Fecal Bacterial Community and Short-Chain Fatty Acid Levels of Healthy Adults

“…VSL#3 has a nominal concentration of 450 billion CFUs per dose, 60% of which was composed of Streptococcus thermophilus and approximately 30% of which was composed of B. animalis subsp. lactis (i.e., at least 135 billion bifidobacterial CFUs per dose) [30]. In the study by Michail and Kenche, 24 subjects with diarrhea-predominant IBS consumed 2 doses per day of VSL#3 for 8 weeks (i.e., nominally, 900 billion viable bacterial cells per day, at least 270 billion of which were represented by bifidobacteria).…”