Characteristic cellular fatty acid composition and an ornithine-containing lipid as a new type of hemagglutinin in Bordetella pertussis.

The fatty acid composition of the total extractable cellular lipids of Bordetella pertussis was very characteristic and was mostly hexadecenoic and hexadecanoic acids (90%) in a ratio of about 1:1. The fatty acid composition of Bordetella parapertussis and Bordetella bronchiseptica differed from that of B. pertussis. The two species were distinguished by the fatty acid composition of cell-bound lipids. The ornithine-containing lipid was characteristic of the genus Bordetella and its main structure was 3-hydroxyhexadecanoic acid amide-linked to ornithine and esterified to the second hexadecanoic acid. The lipid agglutinated human and some animal erythrocytes. The lipid is a new type of hemagglutinin and we proposed that hemagglutination occurred mainly by the hydrophobic interaction between the lipid moiety of the ornithine-containing lipid and phosphatidylcholine in the cell membrane of the erythrocytes. A relatively high content of ornithine-containing lipid was also found in opportunistic pathogens such as Flavobacterium meningosepticum which causes meningitis in babies and children. As the pathogenicity of the opportunistic pathogens is unclear, the ornithine-containing lipid may have an important role in pathogenicity.