Characterization of vaginal Lactobacillus in biologically relevant fluid using surface-enhanced Raman spectroscopy

Area of Science:

• Microbiology
• Biomedical Engineering
• Spectroscopy

Background:

• The vaginal microbiome is vital for women's health, but current monitoring methods are inadequate.
• Existing techniques involve subjective analysis or slow culturing, hindering timely detection of imbalances.
• Alterations in the vaginal microbiome are linked to various health issues throughout a woman's life.

Purpose of the Study:

• To investigate the potential of Surface-Enhanced Raman Spectroscopy (SERS) for analyzing vaginal bacteria.
• To characterize SERS spectra of key vaginal lactobacilli species, Lactobacillus crispatus and Lactobacillus iners.
• To assess SERS's ability to quantify these bacteria in complex biological fluid mimics.

Main Methods:

• Characterization of SERS spectra for Lactobacillus crispatus and Lactobacillus iners at relevant concentrations.
• Testing SERS detection of these bacteria in pure cultures and synthetic vaginal fluid mixtures.
• Utilizing partial least squares regression to analyze spectral data and predict bacterial ratios.

Main Results:

• SERS successfully discriminated between Lactobacillus crispatus and Lactobacillus iners.
• The method accurately predicted bacterial ratios in both pure and complex solutions with <10% error.
• High goodness of prediction (Q^2 > 0.9) was achieved, demonstrating method reliability.

Conclusions:

• SERS provides a rapid and accurate method for monitoring vaginal Lactobacillus species.
• This technique can detect variations in the vaginal microbiome composition.
• SERS holds promise for improving the clinical monitoring of vaginal health.