Cellular fatty acid compositions of an unidentified organism and a bacterium associated with cat scratch disease.

The cellular fatty acid composition of a gram-negative bacterium associated with cat scratch disease was determined by capillary gas chromatography-mass spectrometry (GC-MS). The fatty acid profile of this organism was distinct from those of other bacteria we have tested and was characterized by an unknown acid which was identified as 11-methyloctadec-12-enoic acid. The position of the branched methyl group in this acid was established by GC-MS of the reduced acid, and the location of the double bond was confirmed by GC-MS analysis of dimethyl disulfide derivatives. Another clinical isolate with no known relationship to cat scratch disease but with similar morphological and biochemical features had a similar fatty acid profile, including 11-methyloctadec-12-enoic acid.