The contribution of two phosphorylated surface modifications on the pathogenesis of Campylobacter upsaliensis

Abstract

Campylobacter upsaliensis is a human pathogen most commonly associated with self-limiting gastroenteritis. Despite extensive epidemiological data indicating C. upsaliensis as an emerging pathogen, few studies have examined possible mechanisms of its virulence. The surface of C. upsaliensis is comprised of capsular polysaccharides (CPS) and lipooligosaccharides (LOS), which are likely involved in bacterial interactions with its host and environment. In this study, we demonstrated that the LOS of C. upsaliensis RM3195 is modified with phosphocholine (PCho) and its CPS is decorated with phosphoramidate (MeOPN) residues. These phosphorylated moieties are involved in host cell invasion potentially mediated through the platelet activating factor receptor. Also, PCho and MeOPN conversely affect bacterial survival in human serum; PCho increases C. upsaliensis susceptibility, while MeOPN provides protection. These results suggest that phosphorylated surface modifications play key roles in C. upsaliensis host survival as well as pathogenesis.