Origin, evolution, and distribution of the molecular machinery for biosynthesis of sialylated lipooligosaccharide structures in Campylobacter coli

Campylobacter jejuni and Campylobacter coli are the most common cause of bacterial gastroenteritis worldwide. Additionally, C. jejuni is the most common bacterial etiological agent in the autoimmune Guillain-Barre syndrome (GBS). Ganglioside mimicry by C. jejuni lipooligosaccharide (LOS) is the triggering factor of the disease. LOS-associated genes involved in the synthesis (neuABC) and transfer of sialic acid (sialyltranferases) are essential in C. jejuni to synthesize ganglioside-like LOS. Therefore these genes have been identified as GBS markers. So far, scarce genetic evidence supports C. coli as a GBS causative agent despite being isolated from GBS patients. Here we show that genes putatively involved in sialic acid transfer are widely distributed in the C. coli population. Evidence found herein suggests that a small group of C. coli strains are very likely to express ganglioside mimics, implying that C. coli can potentially trigger GBS. C. coli also presents a larger repertoire of sialyltransferases than C. jejuni and loss of functions of some those LOS-associated genes has happened during adaptation to agriculture niche. Nevertheless, the activity of these sialyltransferases and their role in shaping C. coli population is yet to be explored.