title: Spectroscopic analysis of bacterial biological warfare simulants and the effects of environmental conditioning on a bacterial spectrum.
abstract: The ability to distinguish bacteria from mixed samples is of great interest, especially in the medical and defence arenas. This paper reports a step towards the aim of differentiating pathogenic endospores in situ, to aid any required response for hazard management using infrared spectroscopy combined with multivariate analysis. We describe a proof-of-principle study aimed at discriminating biological warfare simulants from common environmental bacteria. We also report an evaluation of multiple pre-processing techniques and subsequent differences in cross-validation of two pattern recognition models (Support Vector Machines and Principal Component-Linear Discriminant Analysis) for a six-class classification (bacterial classification). These classifications were possible with an average sensitivity of 88.0 and 86.9 %, and an average specificity of 97.6 and 97.5 % for the SVM and the PC-LDA models, respectively. Most spectroscopic models are built upon spectra from bacteria that have been specifically prepared for analysis by a particular method; this paper will comment upon the differences in the bacterial spectrum that occur between specific preparations when the bacteria have spent 30 days in the simulated weather conditions of a hot dry climate.
authors.affiliation: Dstl Porton Down, Salisbury, Wiltshire, UK.
authors.forename: Alastair J S
authors.initials: AJ
authors.lastname: McIntosh
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Barrington
authors.forename: Hilary
authors.initials: H
authors.lastname: Bird
authors.forename: Daniel
authors.initials: D
authors.lastname: Hurst
authors.forename: Phillippa
authors.initials: P
authors.lastname: Spencer
authors.forename: Suzanne H
authors.initials: SH
authors.lastname: Pelfrey
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Baker
mesh_terms: D001419:Bacteria / Q000737:chemistry* / Q000145:classification; D001694:Biological Warfare; D004777:Environment; D015999:Multivariate Analysis; D017550:Spectroscopy, Fourier Transform Infrared / Q000592:standards*