Characterization of pathogenic bacteria by automated headspace concentration-gas chromatography.

Automated headspace concentration-gas chromatography (AHC-GC) was used to profile the volatile metabolites produced by Proteus mirabilis, Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus. Bacterial cultures were incubated in trypticase soy broth and examined at 24 h. The profiles were consistent for each genus examined and variation observed among the different strains of each species was chiefly quantitative. The volatiles were identified by concurrent headspace concentration-gas chromatography-mass spectrometry and consisted mainly of isobutanol, isopentanol, isopentyl acetate, 1-undecene and methyl ketones. There were sufficient differences in the profiles in the 4-6 min elution period to distinguish P. aeruginosa and S. aureus from each other and from the other two bacteria. P. mirabilis and K. pneumoniae typically showed three intense peaks which corresponded to isobutanol, isopentyl acetate and isopentanol. The determination of volatiles by AHC-GC is sensitive, rapid and offers a possible alternative for automatic detection and characterization of pathogenic bacteria.