Lay Summary
Proposal No. IBD-0273R
Principal Investigator: Li Zhang, MBBS, Ph.D
Applicant Organization: The University of New South Wales (Sydney, Australia)
Project Title: Investigation of the possible role of non-jejuni Campylobacter species in inflammatory bowel disease in adult population
Period of Award: August 1, 2009 - August 31, 2011
Studies have shown that intestinal bacterial components play an important role in the development of IBD. However the exact bacterial species that causes IBD remains unknown. As a result, the current management for IBD mainly aims at reduction of inflammation rather than elimination of the causative agent.
Very recently, we have detected a significantly higher prevalence of Campylobacter species in children with CD as compared with controls. These Campylobacter species we have detected in children with CD differ from Campylobacter jejuni, a bacterial species which causes human diarrhea. We therefore termed these Campylobacter species that we have detected in children with CD non-jejuni Campylobacter species. Among the non-jejuni Campylobacter species detected, Campylobacter concisus was of particular interest as this organism was detected in the intestinal biopsies of 51% children with CD as compared with only 2% of controls.In addition to detection of non-jejuni Campylobacter species by PCR-sequencing, we have also isolated four non-jejuni Campylobacter species including Campylobacter concisus. Furthermore, we have detected significantly higher levels of antibodies to C. concisus in children with CD as compared to controls using ELISA. These results suggest that C. concisus may potentially contribute to CD pathogenesis.
In this project, we will extend our study in children into adult population and investigate whether there is an association between non-jejuni Campylobacter species and adult IBD. The specific aims of this project are:
1. To determine the prevalence of non-jejuni Campylobacter species in adult patients with newly diagnosed IBD, relapsing IBD and controls
2. To detect the immune responses specific to C. concisus in the above patients and controls and to determine the immune reactive proteins
3. To investigate whether anti-inflammatory and antibiotic therapies currently used in the treatment of IBD can eradicate non-jejuni Campylobacter species
4. To investigate the susceptibility of isolated non-jejuni Campylobacter species to a range of antibiotics
The proposed project will provide novel information regarding the etiology of human IBD. Furthermore, if the association between non-jejuni Campylobacter species and IBD, which we have discovered in pediatric population, is also found in adult population, an effective antibiotic therapy can be developed and used for the treatment of IBD.