Comparative genomics of Campylobacter concisus : Analysis of clinical strains reveals genome diversity and pathogenic potential

Abstract

In recent years, an increasing number of Campylobacter species have been associated with human gastrointestinal (GI) diseases including gastroenteritis, inflammatory bowel disease, and colorectal cancer. Campylobacter concisus, an oral commensal historically linked to gingivitis and periodontitis, has been increasingly detected in the lower GI tract. In the present study, we generated robust genome sequence data from C. concisus strains and undertook a comprehensive pangenome assessment to identify C. concisus virulence properties and to explain potential adaptations acquired while residing in specific ecological niche(s) of the GI tract. Genomes of 53 new C. concisus strains were sequenced, assembled, and annotated including 36 strains from gastroenteritis patients, 13 strains from Crohn’s disease patients and four strains from colitis patients (three collagenous colitis and one lymphocytic colitis). When compared with previous published sequences, strains clustered into two main groups/genomospecies (GS) with phylogenetic clustering explained neither by disease phenotype nor sample location. Paired oral/faecal isolates, from the same patient, indicated that there are few genetic differences between oral and gut isolates which suggests that gut isolates most likely reflect oral strain relocation. Type IV and VI secretion systems genes, genes known to be important for pathogenicity in the Campylobacter genus, were present in the genomes assemblies, with 82% containing Type VI secretion system genes. Our findings indicate that C. concisus strains are genetically diverse, and the variability in bacterial secretion system content may play an important role in their virulence potential.

Characterization and Phylogenetic Analysis of Campylobacter Species Isolated from Paediatric Stool and Water Samples in the Northwest Province, South Africa

“…They have also been used to detect similarity and differences in genes of particular strains isolated from the same host. For example, Gemmell et al [20] used phylogenetic analysis to investigate the virulence properties and adaptive skills of Campylobacter concisus (C. concisus) isolated from the gastrointestinal tracts of humans and reported that there was no difference between oral and gut C. concisus .…”

Innovative application of nested PCR for detection of Porphyromonas gingivalis in human highly calcified atherothrombotic plaques

“…Interestingly, the microbial community observed in atherothrombotic samples is similar to that observed in subgingival samples [35]. However, no periodontal species have been identified by WGS in vascular samples [36] but they have been identified by WGS in other samples [37]. Some studies also identified gut microbiome members within atherothrombotic samples using WGS, however, the results are mixed [38].…”

Calibrated interdental brushing for the prevention of periodontal pathogens infection in young adults - a randomized controlled clinical trial

“…Therefore, the pathogenic potential may differ depending on the anatomical site in the same host 56 . Depending on the ecological niche, bacteria adapt, leading to varying phenotypic expression and, consequently, different host responses 57 .…”