lpt6, a gene required for addition of phosphoethanolamine to inner-core lipopolysaccharide of Neisseria meningitidis and Haemophilus influenzae.

We previously described a gene, lpt3, required for the addition of phosphoethanolamine (PEtn) at the 3 position on the beta-chain heptose (HepII) of the inner-core Neisseria meningitidis lipopolysaccharide (LPS), but it has long been recognized that the inner-core LPS of some strains possesses PEtn at the 6 position (PEtn-6) on HepII. We have now identified a gene, lpt6 (NMA0408), that is required for the addition of PEtn-6 on HepII. The lpt6 gene is located in a region previously identified as Lgt-3 and is associated with other LPS biosynthetic genes.

Host-derived sialic acid is incorporated into Haemophilus influenzae lipopolysaccharide and is a major virulence factor in experimental otitis media.

Otitis media, a common and often recurrent bacterial infection of childhood, is a major reason for physician visits and the prescription of antimicrobials. Haemophilus influenzae is the cause of approximately 20% of episodes of bacterial otitis media, but most strains lack the capsule, a factor known to play a critical role in the virulence of strains causing invasive H. influenzae disease.