Gas chromatographic-mass spectrometric determination of muramic acid content and pyrolysis profiles for a group of gram-positive and gram-negative bacteria

Abstract

Two gas chromatographic-mass spectrometric methods, one based on chemical derivatisation and the other on analytical pyrolysis, were employed for the characterisation of a diverse group of bacteria. The muramic acid content of some Gram-positive and Gram-negative bacteria (including legionellae) was determined by aldononitrile acetate derivativisation and capillary GC-MS analysis. Muramic acid levels were generally higher in Gram-positive than in Gram-negative bacteria. When applied to the same set of bacteria, pyrolysis GC-MS and non-linear mapping were also able to distinguish Gram-negative from Gram-positive bacteria. The potential of GC-MS techniques for the direct chemical characterisation of bacteria is discussed.