Campylobacter concisus is an extremelyfastidious, gram-negative, curved-rod bacterium which colonises the human oral cavity. It has been isolated from faecal specimens of gastroenteritis patients and few recent studies have suggested its association with inflammatory bowel disease (IBD) due to the higher incidence of its DNA detection in colonic biopsies than in control subjects. However, the role of this bacterium as a human pathogen is still contentious.
In this study, gastrointestinal tract biopsies were collected from patient and control groups attending the Gastroenterology Clinic at the Austin Hospital in Melbourne for endoscopy procedures. In addition, faecal and oral swabs were collected at the same time from all participants. In total, 350 gastrointestinal biopsies, 48 faecal specimens and 51 oral swabs were collected. The presence of C. concisus in all specimens was confirmed by conventional culture and by molecular methods. New PCR techniques were developed to detect this bacterium to the genomospecies level and SDS-PAGE profiles were analysed for C. concisus isolates obtained from different sites in the same patient to evaluate their similarity.
C. concisus DNA was detected in IBD patients (51%) compared to controls (21%) when molecular techniques were used. However, C. concisus was only isolated from three biopsies of 3 different patients using conventional culture methods. Interestingly we were able to obtain a C. concisus isolate from a duodenal biopsy, and to our knowledge this is the first time that this bacterium has been isolated from the duodenum. C. concisus isolates were allocated to either genomospecies A or B based on PCR amplification of the 23S rDNA. Higher numbers of oral isolates were assigned to genomospecies B, while there was no significant difference between the 2 genomospecies (A&B) in intestinal isolates. Further studies are underway to assess the virulence of these isolates.