Raman signatures of Cnm-positive Streptococcus mutans: III, clinical validation

Area of Science:

• Biochemistry
• Microbiology
• Spectroscopy

Background:

• Streptococcus mutans is a key pathogen in dental caries.
• Accurate identification of virulent strains is crucial for effective oral health management.
• Current methods for bacterial identification can be time-consuming and lack state-sensitivity.

Purpose of the Study:

• To evaluate Raman spectroscopy for identifying virulence factors in clinical Streptococcus mutans isolates.
• To correlate spectroscopic findings with genomic data for Cnm-positive strains.
• To explore Raman spectroscopy's potential for rapid oral flora diagnostics.

Main Methods:

• A randomized, double-blind study analyzed 30 clinical Streptococcus mutans samples.
• Samples underwent biofilm purification and in vitro stabilization.
• Raman spectroscopy assessed molecular fingerprints, focusing on oxysulfur molecules, protein disorder, and N-acetylglucosamine simplification.
• Genomic analysis was performed concurrently to identify Cnm-positive strains.

Main Results:

• Raman spectroscopy and genomic analysis identified the same 4 Cnm-positive strains (~13%) out of 30 samples.
• Cnm-positive strains exhibited higher protein disorder, sulfoxidation, and peptidoglycan simplification compared to Cnm-negative strains.
• These molecular changes correlated with increased bacterial virulence, irrespective of serotype.

Conclusions:

• Raman spectroscopy effectively identifies virulent Streptococcus mutans strains based on molecular signatures.
• The technique offers advantages over traditional methods, including speed, label-free analysis, and state sensitivity.
• Raman spectroscopy shows promise for high-risk caries screening and rapid virulence typing of oral bacteria.