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Infrared Spectroscopy in Microbiology

Biomedical Spectroscopy

  1. Dieter Naumann

Published Online: 15 SEP 2006

DOI: 10.1002/9780470027318.a0117

Encyclopedia of Analytical Chemistry

Encyclopedia of Analytical Chemistry

How to Cite

Naumann, D. 2006. Infrared Spectroscopy in Microbiology. Encyclopedia of Analytical Chemistry. .

Author Information

  1. Robert Koch-Institute, Berlin, Germany

Publication History

  1. Published Online: 15 SEP 2006

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Infrared (IR) spectra of intact microbial cells are highly specific fingerprint-like signatures which are used to differentiate, classify, and identify diverse microbial species and strains. Microbial IR spectra are also useful to (1) detect in situ intracellular compounds or structures such as inclusion bodies, storage materials, and endospores, (2) monitor and quantify metabolically released CO2 in response to various different substrates, and (3) characterize growth-dependent phenomena and cell–drug interactions. The characteristic information, useful for microbial characterizations, is generally distributed over the entire IR region of the electromagnetic spectrum, i.e. over the near-infrared (NIR), mid-infrared (MIR), and far-infrared (FIR). The spectral traits can be systematically extracted from the typically broad and complex spectral contours applying resolution enhancement techniques, difference spectroscopy, and pattern recognition methods such as factor-analysis and cluster-analysis, and artificial neural networks (ANNs). Additional applications arise by means of a light microscope coupled to the IR spectrometer. IR spectra of microcolonies containing less than 103 cells are obtained from colony replica by a stamping technique that transfers microcolonies growing on culture plates to a special IR-sample holder. Using a computer-controlled x,y-stage together with mapping and video techniques, the fundamental tasks of microbiological analysis, namely detection, enumeration, and differentiation of microorganisms, are perspectively integrated in one single apparatus.