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Bifidobacteria Strain Typing by Fourier Transform Infrared Spectroscopy
Francesca Deidda1, Nicole Bozzi Cionci2, Miriam Cordovana3
1Probiotical Research S.r.L., Novara, Italy.
Frontiers in Microbiology
|September 30, 2021
Summary
Fourier transform infrared (FTIR) spectroscopy offers a powerful method for microbial typing, especially for probiotics like bifidobacteria. This technique can differentiate bacterial strains with high accuracy, even when traditional genetic methods fall short.
Area of Science:
- Microbiology
- Spectroscopy
- Genomics
Background:
- Fourier transform infrared (FTIR) spectroscopy is increasingly used for microbial typing, moving beyond its traditional chemical analysis applications.
- This technique analyzes the vibrational modes of molecular bonds in bacterial cells, offering a rapid and cost-effective method.
- FTIR spectroscopy is particularly relevant for industrial applications, especially in the characterization of probiotic microorganisms.
Purpose of the Study:
- To evaluate the discriminatory power of FTIR spectroscopy for bacterial strain typing.
- To compare FTIR spectroscopy with established genotyping methods: pulsed-field gel electrophoresis (PFGE), whole-genome sequencing (WGS), and multilocus sequence typing (MLST).
- To assess the potential of FTIR for typing bifidobacterial strains, important in the probiotic industry.
Main Methods:
- Fourier transform infrared (FTIR) spectroscopy was applied to bacterial cell samples.
- Comparative analysis was performed against PFGE, WGS, and MLST for strain differentiation.
- The study focused on strains of *Bifidobacterium longum* subsp. *longum* and *Bifidobacterium animalis* subsp. *lactis*.
Main Results:
- FTIR spectroscopy successfully discriminated between strains of *B. longum* subsp. *longum*, similar to PFGE, WGS, and MLST.
- For *B. animalis* subsp. *lactis*, FTIR spectroscopy demonstrated superior discriminatory power, identifying individual strains where other methods were non-discriminatory.
- FTIR analysis revealed phenotypic variations at the cell surface, acting as a unique strain-specific barcode.
Conclusions:
- FTIR spectroscopy is a valuable and often more informative tool than traditional genotyping methods for bacterial strain typing, particularly for certain probiotic species.
- The technique's ability to discern subtle phenotypic differences makes it highly effective for tracking and identifying specific bacterial strains.
- This study highlights FTIR spectroscopy as a promising method for strain-level analysis in bifidobacteria, with significant implications for the probiotic industry.
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