[Gas-liquid chromatography in microbiological diagnosis].

With gas-liquid chromatography, it is possible to detect chemical compounds which are specific of micro-organisms: either metabolic products, or structural components. This technique permits to simplify the diagnosis: it is the case for anaerobic bacteria, where the analysis of the fermentation acids produced in a 48 hours liquid culture enables to rapidly establish the diagnosis, at least as far as the genus is concerned. It may also increase the accuracy of the diagnosis by searching such or such metabolite or structural component which are specific of a species or a sub-species. Some authors have already determined automatic systems of bacterial identification; these systems are based on a computer analysis of the chromatographic profile of cellular fatty acids. Finally it is important to emphasize that liquid-gas chromatography may markedly shorten the delay of identification by allowing, in some cases, a direct diagnosis in pathological samples.