Biomedical Optics Express
Spectroscopy, Medical optics and biotechnology, Chemometrics, Raman spectroscopy
The determination of bacterial identity at the strain level is still a complex and time-consuming endeavor. In this study, visible wavelength spontaneous Raman spectroscopy has been used for the discrimination of four closely related Escherichia coli strains: pathogenic enterohemorrhagic E. coli O157:H7 and non-pathogenic E. coli C, E. coli Hfr K-12, and E. coli HF4714. Raman spectra from 600 to 2000 cm-1 were analyzed with two multivariate chemometric techniques, principal component-discriminant function analysis and partial least squares-discriminant analysis, to determine optimal parameters for the discrimination of pathogenic E. coli from the non-pathogenic strains. Spectral preprocessing techniques such as smoothing with windows of various sizes and differentiation were investigated. The sensitivity and specificity of both techniques was in excess of 95%, determined by external testing of the chemometric models. This study suggests that spontaneous Raman spectroscopy with visible wavelength excitation is potentially useful for the rapid identification and classification of clinically-relevant bacteria at the strain level.
Funding Reference Number
Rehse, Steven; Hamasha, Khozima; Mohaidat, Qassem I.; Putnam, Russell A.; Woodman, Ryan C.; and Palchaudhuri, Sunil. (2013). Sensitive and specific discrimination of pathogenic and nonpathogenic Escherichia coli using Raman spectroscopy - a comparison of two multivariate analysis techniques. Biomedical Optics Express, 4, 481-489.