Genomic Evidence for the Emergence and Evolution of Pathogenicity and Niche Preferences in the Genus Campylobacter

Abstract

The genus Campylobacter includes some of the most relevant pathogens for human and animal health; the continuous effort in their characterization has also revealed new species putatively involved in different kind of infections. Nowadays, the available genomic data for the genus comprise a wide variety of species with different pathogenic potential and niche preferences. In this work, we contribute to enlarge this available information presenting the first genome for the species Campylobacter sputorum bv. sputorum and use this and the already sequenced organisms to analyze the emergence and evolution of pathogenicity and niche preferences among Campylobacter species. We found that campylobacters can be unequivocally distinguished in established and putative pathogens depending on their repertory of virulence genes, which have been horizontally acquired from other bacteria because the nonpathogenic Campylobacter ancestor emerged, and posteriorly interchanged between some members of the genus. Additionally, we demonstrated the role of both horizontal gene transfers and diversifying evolution in niche preferences, being able to distinguish genetic features associated to the tropism for oral, genital, and gastrointestinal tissues. In particular, we highlight the role of nonsynonymous evolution of disulphide bond proteins, the invasion antigen B (CiaB), and other secreted proteins in the determination of niche preferences. Our results arise from assessing the previously unmet goal of considering the whole available Campylobacter diversity for genome comparisons, unveiling notorious genetic features that could explain particular phenotypes and set the basis for future research in Campylobacter biology.

Genomic and clinical evidence uncovers the enterohepatic species Helicobacter valdiviensis as a potential human intestinal pathogen

“…The genomic characterization of H. valdiviensis revealed that HGTs from Campylobacter species involved key virulence‐associated genes. Similar evolutionary events have been previously reported between other Helicobacter and Campylobacter species, highlighting the importance of DNA introgression between species co‐occurring in the same hosts . In particular, the CDT genes for which we detected homoplasy are placed next to a phage and an ankyrin domain gene in the genome of H. valdiviensis , constituting a genomic context compatible with HGTs .…”

Hierarchical genomic analysis of carried and invasive serogroup A Neisseria meningitidis during the 2011 epidemic in Chad

“…A previous study of the pharyngeal carriage of members of the Neisseria genus found that there was an inverse relationship between carriage of Nm and other non-pathogenic Neisseria species by age group which indicate a potential role that other microbes may play in modulating Nm carriage and could explain the age difference seen in this study [34]. Further studies, similar to those undertaken on the gut microbiota [35, 36], might address this issue. DNA microarray studies have identified a bacteriophage that was mostly found in genomes from the hyper-invasive clonal complexes [2].…”

The microbial community structure of the cotton rat nose

“…However, Campylobacter not only colonizes the gut of animals. Campylobacter rectus and C. gracilis have been associated with periodontal diseases and infections in the oral cavity (Siqueira and Rocas, 2003), and the species C. concisus, C. curvus and C. showae have been related to the oral cavity too (Iraola et al, 2014). Campylobacter sp.…”