Large sequence diversity within biosynthesis locus and common biochemical features of Campylobacter coli lipooligosaccharides

Despite the importance of lipooligosaccharides (LOS) in the pathogenicity of campylobacteriosis, little is known about the genetic and phenotypic diversity of LOS in C. coli In this study, we investigated the distribution of LOS locus classes among a large collection of unrelated C. coli isolates sampled from several different host species. Furthermore, we paired C. coli genomic information and LOS chemical composition for the first time to investigate possible associations between LOS locus classes sequence diversity and biochemical heterogeneity. After identifying three new LOS locus classes, only 85% of the 144 isolates tested were assigned to a class, suggesting higher genetic diversity than previously thought. This genetic diversity is at the basis of a completely unexplored LOS structure heterogeneity. Mass spectrometry analysis of the LOS of nine isolates, representing four different LOS classes, identified two features distinguishing C. coli LOS from C. jejuni's. GlcN-GlcN disaccharides were present in the lipid A backbone in contrast to the GlcN3N-GlcN backbone observed in C. jejuni Moreover, despite that many of the genes putatively involved in Qui3pNAcyl were apparently absent from the genomes of various isolates, this rare sugar was found in the outer core of all C. coli Therefore, regardless the high genetic diversity of LOS biosynthesis locus in C. coli, we identified species-specific phenotypic features of C. coli LOS which might explain differences between C. jejuni and C. coli in terms of population dynamics and host adaptation.

IMPORTANCE: Despite the importance of C. coli to human health and its controversial role as a causative agent of the Guillain-Barré syndrome, little is known about the genetic and phenotypic diversity of C. coli LOS. Therefore, we paired C. coli genomic information and LOS chemical composition for the first time to address this paucity of information. We identified two species-specific phenotypic features of C. coli LOS, which might contribute to elucidating the reasons behind the differences between C. jejuni and C. coli in terms of population dynamics and host adaptation.