Enterobacteria differentiated by gas-liquid chromatography of metabolites

The short chain acids of 47 strains within the family Enterobacteriaceae grown on prereduced, anaerobically sterilized peptone yeast-extract glucose broth (PRAS PY G) under standardized conditions were determined by gas-liquid chromatography (GLC). The bacteria could be subdivided into six groups on the basis of their metabolites. Acetate, lactate, succinate and ethanol were detected from all strains and constituted a set of basic fermentation products, P, mirabilis, in addition, produced propanol, and was distinguished from P. morganii which formed propionate, pyruvate, methanol and oxalacetate, P. rettgeri only produced methanol along with the basic metabolites. Butanol and 2, 3-butanediol were characteristic of bacteria with the butanediol modification of mixed-acid fermentation, but could only be detected after anaerobic growth. Additionally, Hafnia produced propanol, which differentiated these strains from Enterobacter, Klebsiella, Serratia and Erwinia. The results indicate that GLC of metabolites may render supplementary information utilizable in identification of enteric bacteria.