Cellular fatty acids of nonpathogenic Neisseria

The cellular fatty acid composition of 33 strains representing 15 species of nonpathogenic Neisseria was examined by gas–liquid chromatography. Each isolate was characterized by standard biochemical and cultural methods. Media composition influenced both the qualitative and quantitative fatty acid content of some strains examined. However, on the basis of their fatty acid composition, the species formed the same general groups regardless of the media used. N. flavescens, N. canis, N. subflava, N. flava, N. sicca, N. perflava. N. cuniculi, N. mucosa, and N. cinerea formed one fairly homogeneous group with similar fatty acid composition. Palmitic, a monoenoic 16-carbon, a monoenoic 18-carbon, β-hydroxylauric, lauric, and myristic acids were the major fatty acids present and constituted 85–90% of the total fatty acids found. N. lactamicus grown in trypticase soy broth (TSB) could be included with this general group, but it differed from all other species when grown on plates of Difco GC medium base with 1% defined supplement (GCBDS). N. catarrhalis, N. caviae, and N. ovis formed a second homogeneous group which was characterized by the presence of decanoic acid in addition to the fatty acids found in the other species. The members of this second group were further characterized after growth on GCBDS plates by the presence of large amounts of monoenoic 17-carbon acid. N. denitrificans and N. haemolysans lacked β-hydroxylauric acid, a fatty acid which has been found in relatively large amounts in over 100 isolates of various Neisseria species examined in this laboratory.