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VSL3 pharma



Stefania Arioli, Stefano Colombo, Giorgio Gargari, Giulia Della Scala, Willem de Vos, Diego Mora


To show consistency in the quality, viability and composition of the multispecies probiotic product VSL#3 various batches of the multispecies probiotic VSL#3 were analyzed in detail and derived from productions in the USA and Italy. The product batches have been tested using a series of microbiological, phylogenetic and metagenetics methods. In addition, Lactobacillus helveticus and Lactobacillus acidophilus S-layer proteins, which are known to exert anti-inflammatory effects by reducing the activation of NF-KB on the intestinal epithelial Caco-2 cell line, have been extracted, visualized and identified.


The different batches tested were all found to contain a common bacterial community structure based on the presence of the following species Streptococcus thermophilus, Lactobacillus acidophilus, Lactobacillus paracasei, Lactobacillus plantarum, Lactobacillus helveticus, Bifidobacterium breve and Bifidobacterium animalis subsp. lactis. The stability of the batches was confirmed by Flow Cytometry (FCM), and viable cells were always above the value of 2 x 1010 event/g. FCM analysis allowed to identify and quantify live, dead and damaged cell populations in the multi-strain probiotic formulation and using species-specific-qPCR was possible to address which was the viability of each species.

The L. helveticus and L. acidophilus S-layer protein SIpA were detected in each VSL#3 batches tested, representing the majority of the surface proteins, thus highlighting that this relevant immunomodulatory factors were not subjected to degradation during the preparation and the shelf-life of the multi-strain probiotic formulation. Likewise, urease activity peculiar of the species S. thermophilus ms stable in all VSL#3 batches tested.


In conclusion, stability, molecular and taxonomic comparative analysis show that VSL#3 is reliably and reproducibly produced in different parts of the world. More importantly, the assessment and the quantification of putative probiotic molecular markers (S-layer proteins and urease) directly in the product, i. e. without a cultivation step, represents a first example of quality control in a probiotic product targeted to “probiotic-traits”, when quality controls are currently directed and limited to the evaluation of cell viability. In addition, the quantification of the viability by FCM combined with a cell sorting and a qPCR quantification of each bacterial species in the blend, represent a further new quality control step for a multi-strain probiotic product.
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