Long-chain fatty acids of peptococci and peptostreptococci.

The long-chain fatty acids extracted from the whole cells of 12 clinically significant species of peptococci and peptostreptococci were characterized by gas-liquid chromatography. The resulting methylated fatty acid profiles (and some unidentified compounds) of 82 strains allowed the 12 species to be separated into four groups. Fifteen strains of Peptostreptococcus anaerobius were placed in group I because they had a unique, prominent compound that occurred in the area where a C8 to C10 fatty acid would be expected. Group II, consisting of Peptostreptococcus intermedius, Peptostreptococcus micros, Peptostreptococcus parvulus, Peptococcus morbillorum, and Peptococcus constellatus, produced C14, C16:1, C18:1, and C18 fatty acids. Peptococcus prevotii, Peptococcus variabilus, Peptococcus magnus, Peptococcus asaccharolyticus, and Peptostreptococcus productus were placed in group III because they contained three to six additional, unidentified compounds that strikingly differentiated them from group II. Peptococcus saccharolyticus was the single species assigned to group IV because it yielded C14, C16, C18:1, C18, and C20 fatty acids and a prominent unidentified peak that occurred between C14 and C16 fatty acids. This study indicated that cellular long-chain fatty acids may be an important tool in clarifying the taxonomy of the peptococci and peptostreptococci.