Development of omics-based protocols for the microbiological characterization of multi-strain formulations marketed...

Area of Science:

• Microbiology
• Biotechnology
• Genomics

Background:

• Commercial interest in multi-strain probiotics is high, but quality evaluation methods lag behind.
• Complex probiotic formulations require robust characterization to ensure product quality and safety.
• VSL#3, a well-known multi-strain probiotic, was chosen as a model for developing quality assessment protocols.

Purpose of the Study:

• To establish microbiological and molecular characterization methods for complex multi-strain probiotic formulations.
• To assess the quality, strain identity, safety, and composition of the VSL#3 probiotic product.
• To develop protocols applicable to other complex probiotic products on the market.

Main Methods:

• Shotgun metagenomics using deep Illumina sequencing for DNA analysis.
• Single-cell analysis for evaluating bacterial viability.
• Enzyme activity assays (β-galactosidase, urease) for process reproducibility monitoring.
• Metaproteomics with advanced mass spectrometry for protein profiling.

Main Results:

• Successfully identified over 1600 protein groups, confirming the presence of all strains in VSL#3.
• Metagenomic and metaproteomic analyses confirmed strain identity, safety, and composition.
• Minor variations (3.2%) in protein profiles were mainly linked to small shifts in strain abundance.
• Developed and validated protocols for assessing key quality criteria in complex probiotics.

Conclusions:

• The developed protocols provide a framework for defining and ensuring the quality of complex multi-strain probiotic formulations.
• This study represents a significant step towards standardizing the quality control of products like VSL#3.
• Robust characterization methods are essential to meet the growing demand for reliable probiotic supplements.