title: Raman spectroscopic measurement of relative concentrations in mixtures of oral bacteria.
abstract: Near-infrared Raman spectroscopy has been used for species identification of pure microbial specimens for more than a decade. More recently, this optical method has been extended to the analysis of specimens containing multiple species. In this report, we demonstrate rapid, reagent-free quantitative analysis of a simplified model of oral plaque containing three oral bacteria species, S. mutans, S. sanguis, and S. gordonii, using near-infrared Raman spectroscopy. Raman spectra were acquired from bacterial mixtures in 200 seconds. A prediction model was calibrated by the partial least squares method and validated by additional samples. On a scale from 0 to 1, relative fractions of each species could be predicted with a root mean square error of 0.07. These results suggest that near-infrared Raman spectroscopy is potentially useful in quantification of microbial mixtures in general and oral plaques in particular.
authors.affiliation: The Institute of Optics, University of Rochester, Rochester, NY 14627, USA.
authors.forename: Qingyuan
authors.initials: Q
authors.lastname: Zhu
authors.forename: Robert G
authors.initials: RG
authors.lastname: Quivey
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Berger
mesh_terms: D003773:Dental Plaque / Q000737:chemistry / Q000382:microbiology*; D009055:Mouth / Q000382:microbiology*; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013291:Streptococcus / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D013295:Streptococcus mutans / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D013298:Streptococcus sanguis / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism