Novel Campylobacter concisus lipooligosaccharide is a determinant of inflammatory potential and virulence

Abstract

The pathogenicity of , increasingly found in the human gastrointestinal (GI) tract, is unclear. Some studies indicate that its role in GI conditions has been underestimated, whereas others suggest that the organism has a commensal-like phenotype. For the enteropathogen, the lipooligosaccharide (LOS) is a main driver of virulence. We investigated the LOS structure of four clinical isolates and correlated the inflammatory potential of each isolate with bacterial virulence. Mass spectrometric analyses of lipid A revealed a novel hexa-acylated diglucosamine moiety with two or three phosphoryl substituents. Molecular and fragment ion analysis indicated that the oligosaccharide portion of the LOS had only a single phosphate and lacked phosphoethanolamine and sialic acid substitution, which are hallmarks of the LOS. Consistent with our structural findings, LOS and live bacteria induced less TNF-α secretion in human monocytes than did Furthermore, the bacteria were less virulent than in a infection model. The correlation of the novel lipid A structure, decreased phosphorylation, and lack of sialylation along with reduced inflammatory potential and virulence support the significance of the LOS as a determinant in the relative pathogenicity of.

Species-Level Salivary Microbial Indicators of Well-Resolved Periodontitis: A Preliminary Investigation

“…The oral cavity is considered a potential reservoir (Zhang et al, 2010). It can act as an opportunistic pathogen in immune-inflammatory and epithelial cell dysregulation (Deshpande et al, 2016; Brunner et al, 2018). A rise in its abundance after successful periodontitis therapy has been reported (Tanner et al, 1987), again supporting the premise that periodontal treatment may result in specific differences in microbiome composition.…”

Campylobacter concisus

“…Furthermore, the C. concisus bacteria were less virulent than C. jejuni. According to the authors, all of those findings support the significance of the LOS as a determinant in the relative pathogenicity of C. concisus [54]. Kaakoush et al described a comprehensive global profile of innate immune responses to C. concisus infection in differentiated THP-1 macrophages infected with an adherent and invasive strain of C. concisus.…”

Conventional and Molecular Detection Methods of the Opportunistic Bacterial Pathogen Campylobacter concisus

“…Matrix-assisted laser desorption/ionisation (MALDI) with time-of-flight mass spectrometry (TOFMS) is a technique developed more than three decades ago, which can be used to detect and characterise pathogens on the basis of larger biomolecules. Few studies proved the feasibility to identify C. concisus using MALDI-TOF-MS analysis of protein biomarkers from protein extracts of cell lysates or from whole cells [59][60][61]. The first attempt was in 2005 [62] using MALDI-TOF-MS to identify a number of Campylobacter species from their protein biomarkers, where they have identified a 10.5-kDa protein as the DNA-binding protein HU, and the potential species-identifying biomarker ions (SIBI) for C. concisus strains.…”

“…However, no distinguished biomarker has been identified to differentiate between the two genomospecies which can be easily differentiated by the 23S rDNA PCR [28]. Recently the lipo-oligosaccharide (LOS) structure (an important virulence factor which activates TLR4) of C. concisus clinical isolates correlated the inflammatory potential of each isolate with bacterial virulence by MALDI-TOF MS [61]. The presence of multiple bands in the SDS-PAGE profiles of C. concisus and C. jejuni LOS indicated their heterogeneity.…”