title: Campylobacter concisus utilizes blood but not short chain fatty acids despite showing associations with Firmicutes taxa.
abstract: Campylobacter concisus is a member of the oral microbiota that has been associated with the development of inflammatory bowel diseases. However, the role of the bacterium in disease aetiology remains poorly understood. Here, we examine optimal conditions for the growth of C. concisus, and the pathogenic potential of this bacterium in human gastrointestinal cells from the upper tract. Further, the presence of C. concisus in the lower tract of Crohn's disease (CD) patients undergoing therapy is observed, and the associations of C. concisus with the abundance of other microbial taxa and compounds they produce are evaluated. C. concisus strains had the ability to tolerate moderate levels of acidity, adhere to and invade esophageal and gastric cells; however, these properties did not correlate with their pathogenic potential in intestinal cells. The presence of the bacterium in the lower gut of CD patients was associated with an increased relative abundance of Faecalibacterium and Lachnospiraceae incertae sedis. Short chain fatty acids that can be produced by these microbial species did not appear to be responsible for this association. However, we identified genetic similarity between C. concisus and Firmicutes, specifically within aspartate and glutamate racemases. The potential pathogenesis of C. concisus in the upper gastrointestinal tract, and the responsiveness of the bacterium to therapy in a subset of CD patients warrant further investigation into whether this bacterium has a causal role in disease or its presence is incidental.
authors.affiliation: School of Medical Sciences, UNSW Australia, Sydney, NSW 2052, Australia.
authors.forename: Nadeem O
authors.initials: NO
authors.lastname: Kaakoush
authors.affiliation: Nuclear Magnetic Resonance Spectroscopy Facility, Mark Wainwright Analytical Centre, UNSW Australia, Sydney, NSW 2052, Australia.
authors.forename: Donald S
authors.initials: DS
authors.lastname: Thomas
authors.affiliation: School of Biotechnology and Biomolecular Sciences, UNSW Australia, Sydney, NSW 2052, Australia.
authors.forename: Mahmoud M
authors.initials: MM
authors.lastname: Ruzayqat
authors.affiliation: School of Biotechnology and Biomolecular Sciences, UNSW Australia, Sydney, NSW 2052, Australia.
authors.forename: David
authors.initials: D
authors.lastname: Lynch
authors.affiliation: School of Women's and Children's Health, UNSW Australia, Sydney, Australia.
authors.forename: Steven T
authors.initials: ST
authors.lastname: Leach
authors.affiliation: Department of Gastroenterology, Sydney Children's Hospital, Sydney, Australia.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Lemberg
authors.affiliation: School of Women's and Children's Health, UNSW Australia, Sydney, Australia.|Department of Gastroenterology, Sydney Children's Hospital, Sydney, Australia.|Department of Paediatrics, University of Otago, Christchurch, New Zealand.
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Day
authors.affiliation: School of Biotechnology and Biomolecular Sciences, UNSW Australia, Sydney, NSW 2052, Australia.
authors.forename: Hazel M
authors.initials: HM
authors.lastname: Mitchell
mesh_terms: D001422:Bacterial Adhesion / Q000502:physiology; D001769:Blood / Q000382:microbiology*; D002167:Campylobacter / Q000145:classification* / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity*; D002169:Campylobacter Infections / Q000382:microbiology; D002478:Cells, Cultured; D000068016:Eubacteriales / Q000302:isolation & purification; D003424:Crohn Disease / Q000382:microbiology*; D000070036:Faecalibacterium / Q000302:isolation & purification; D005232:Fatty Acids, Volatile / Q000378:metabolism*; D000068536:Bacillota / Q000145:classification* / Q000235:genetics; D041981:Gastrointestinal Tract / Q000166:cytology / Q000382:microbiology*; D006801:Humans
chemical_list: D005232:Fatty Acids, Volatile