title: Rapid identification of urinary tract infection bacteria using hyperspectral whole-organism fingerprinting and artificial neural networks.
abstract: Three rapid spectroscopic approaches for whole-organism fingerprinting-pyrolysis mass spectrometry (PyMS), Fourier transform infra-red spectroscopy (FT-IR) and dispersive Raman microscopy--were used to analyse a group of 59 clinical bacterial isolates associated with urinary tract infection. Direct visual analysis of these spectra was not possible, highlighting the need to use methods to reduce the dimensionality of these hyperspectral data. The unsupervised methods of discriminant function and hierarchical cluster analyses were employed to group these organisms based on their spectral fingerprints, but none produced wholly satisfactory groupings which were characteristic for each of the five bacterial types. In contrast, for PyMS and FT-IR, the artificial neural network (ANN) approaches exploiting multi-layer perceptrons or radial basis functions could be trained with representative spectra of the five bacterial groups so that isolates from clinical bacteriuria in an independent unseen test set could be correctly identified. Comparable ANNs trained with Raman spectra correctly identified some 80% of the same test set. PyMS and FT-IR have often been exploited within microbial systematics, but these are believed to be the first published data showing the ability of dispersive Raman microscopy to discriminate clinically significant intact bacterial species. These results demonstrate that modern analytical spectroscopies of high intrinsic dimensionality can provide rapid accurate microbial characterization techniques, but only when combined with appropriate chemometrics.
authors.affiliation: Institute of Biological Sciences, University of Wales, Aberystwyth, Ceredigion SY23 3DD, UK.
authors.forename: Royston
authors.initials: R
authors.lastname: Goodacre
authors.affiliation: Institute of Biological Sciences, University of Wales, Aberystwyth, Ceredigion SY23 3DD, UK.
authors.forename: Éadaoin M
authors.initials: ÉM
authors.lastname: Timmins
authors.affiliation: Institute of Biological Sciences, University of Wales, Aberystwyth, Ceredigion SY23 3DD, UK.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Burton
authors.affiliation: Institute of Biological Sciences, University of Wales, Aberystwyth, Ceredigion SY23 3DD, UK.
authors.forename: Naheed
authors.initials: N
authors.lastname: Kaderbhai
authors.affiliation: Institute of Biological Sciences, University of Wales, Aberystwyth, Ceredigion SY23 3DD, UK.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Woodward
authors.affiliation: Institute of Biological Sciences, University of Wales, Aberystwyth, Ceredigion SY23 3DD, UK.
authors.forename: Douglas B
authors.initials: DB
authors.lastname: Kell
authors.affiliation: Bronglais General Hospital, Aberystwyth, Ceredigion SY23 lER, UK.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Rooney
mesh_terms: D015373:Bacterial Typing Techniques; D016000:Cluster Analysis; D004755:Enterobacteriaceae / Q000145:classification* / Q000302:isolation & purification; D004756:Enterobacteriaceae Infections / Q000382:microbiology; D016983:Enterococcus / Q000145:classification* / Q000302:isolation & purification; D016908:Gram-Positive Bacterial Infections / Q000382:microbiology; D006801:Humans; D013058:Mass Spectrometry; D016571:Neural Networks, Computer; D011549:Pseudomonas / Q000145:classification* / Q000302:isolation & purification; D011552:Pseudomonas Infections / Q000382:microbiology; D017550:Spectroscopy, Fourier Transform Infrared; D013057:Spectrum Analysis; D013059:Spectrum Analysis, Raman; D014552:Urinary Tract Infections / Q000382:microbiology*; D014556:Urine / Q000382:microbiology