Detection of <i>Campylobacter concisus </i>and other <i>campylobacter </i>species in colonic biopsies from adults with ulcerative colitis

Introduction: The critical role of bacteria in the pathogenesis of ulcerative colitis (UC) is well recognized, but an individual causative microorganism has not been singled out so far. Campylobacter concisus and other non-jejuni species of Campylobacter have been implicated as putative aetiological agents in inflammatory bowel disease in children, but such studies have not been addressed in adults. This study investigated the prevalence of Campylobacter species in colonic biopsy samples from adults with UC and healthy controls.Methods: Adult patients who were undergoing diagnostic colonoscopy were recruited for the study, which included 69 patients with histologically proven UC and 65 healthy controls. DNA was extracted from the biopsy samples and subjected to Campylobacter genus specific and Campylobacter concisus specific polymerase chain reaction and sequencing. Results: Detection of all Campylobacter DNA utilising genus specific primers was significantly higher in cases of UC, with a prevalence of 73.9% (51/69) compared to 23.1% (15/65) in controls (p = 0.0001). Nested PCR for C. concisus DNA was positive in 33.3% (23/69) of biopsy samples from subjects with UC, which was significantly higher than the prevalence rate of 10.8% (7/65) from controls (p = 0.0019). Sequencing of the remaining Campylobacter positive samples revealed that Campylobacter ureolyticus was positive in 21.7% (15/69) of samples from UC subjects as opposed to 3.1% (2/65) in controls (p = 0.0013). Mixed Campylobacter species were more common in UC patients, 20.3% (14/69) as compared to controls 4.6% (3/65) (p = 0.0084). Conclusion: The higher prevalence of Campylobacter genus and more specifically C. concisus and C. ureolyticus in biopsy samples from adults with UC suggests these genera of bacteria may be involved in the chronic inflammation that is characteristically seen in UC. To the best of our knowledge this is the first report of this association of C. concisus and C. ureolyticus with UC in adults.