Characterization of Xenorhabdus and Photorhabdus bacteria by Fourier transform mid-infrared spectroscopy with attenuated total reflection (FT-IR/ATR)

The use of Fourier transform mid-infrared spectroscopy with attenuated total reflection for characterizing entomopathogenic bacteria from genera Xenorhabdus and Photorhabdus is evaluated for the first time. The resulting spectra of Xenorhabdus poinarii and Photorhabdus luminiscens were compared with the spectrum of Escherichia coli samples. The absorption spectra generated by the bacteria samples, were very different at the region below 1400 cm−1 which represents the stretching vibrations of phosphate and carbohydrates. Star diagrams of the fingerprint section of nematodes spectra (between 1350 and 1650 cm−1) for separation between spectra was used and showed to be a useful tool for classification purposes.

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► Entomopathogenic bacteria were characterized by FTIR/ATR for the first time.
► Differences on the biochemical composition were detected and compared.
► A new approach using star diagrams were employed for differentiation between bacterial genera.
► This method can be used for classification, analysis of metabolic processes or biochemical changes.