Characterization of microorganisms using UV resonance Raman spectroscopy and chemometrics

The past decade has seen an increased interest in the application of several physicochemical analytical techniques for the rapid detection and identification of microorganisms. We report the development of UV resonance Raman (UVRR) spectroscopy for the reproducible acquisition of information rich Raman fingerprints from endospore-forming bacteria belonging to the genera Bacillus and Brevibacillus. UVRR was conducted at 244 nm, and spectra were collected in typically 60 s. Cluster analyses of these spectra showed that UVRR spectroscopy could be used to discriminate between these microorganisms to species level, and the clustering pattern from this phenotypic classification was highly congruent with phylogenetic trees constructed from 16S rDNA sequence analysis. Therefore, we conclude that UVRR spectroscopy when coupled with chemometrics constitutes a powerful approach to the characterization and speciation of microorganisms.