ABSTRACT
Campylobacter jejuni and Campylobacter coli are the most common cause of bacterial gastroenteritis in the world. Ganglioside mimicry by C. jejuni lipooligosaccharide (LOS) is the triggering factor of Guillain-Barré syndrome (GBS), an acute polyneuropathy. Sialyltransferases from the glycosyltransferase (GT) family 42 are essential for the expression of ganglioside mimics in C. jejuni. Recently, two novel GT-42 genes, cstIV and cstV, have been identified in C. coli. Despite being present in ∼11% of currently available C. coli genomes, the biological role of cstIV and cstV is unknown. Here, we show that CstIV and CstV are involved in LOS biosynthesis. Additionally, cstV is associated with LOS sialylation, while cstIV is linked to the addition of a diacetylated nonulosonic acid residue.