Chlamydia trachomatis infection: is it relevant in irritable bowel syndrome?

The possible role of bacteria, viruses, and parasites in initiation and exacerbation of irritable bowel syndrome

Irritable bowel syndrome (IBS) is a prolonged and disabling functional gastrointestinal disorder with the incidence rate of 18% in the world. IBS could seriously affect lifetime of patients and cause high economic burden on the community. The pathophysiology of the IBS is hardly understood, whereas several possible mechanisms, such as visceral hypersensitivity, irregular gut motility, abnormal brain-gut relations, and the role of infectious agents, are implicated in initiation and development of this syndrome. Different studies demonstrated an alteration in B-lymphocytes, mast cells (MC), T-lymphocytes, and cytokine concentrations in intestinal mucosa or systemic circulation that are likely to contribute to the formation of the IBS. Therefore, IBS could be developed in those with genetic predisposition. Infections' role in initiation and exacerbation of IBS has been investigated by quite several clinical studies; moreover, the possible role of some pathogens in development and exacerbation of this disease has been described. It appears that the main obligatory pathogens correspond with the IBS disease, Clostridium difficile, Escherichia coli, Mycobacterium avium subspecies paratuberculosis, Campylobacter concisus, Campylobacter jejuni, Chlamydia trachomatis, Helicobacter pylori, Pseudomonas aeruginosa, Salmonella spp, Shigella spp, and viruses, particularly noroviruses. A number of pathogenic parasites (Blastocystis, Dientamoeba fragilis, and Giardia lamblia) may also be involved in the progression and exacerbation of the disease. Based on the current knowledge, the current study concludes that the most common bacterial, viral, and parasitic pathogens may be involved in the development and progression of IBS.

Chlamydia trachomatis antigens in enteroendocrine cells and macrophages of the small bowel in patients with severe irritable bowel syndrome

BACKGROUND

Inflammation and immune activation have repeatedly been suggested as pathogentic factors in irritable bowel syndrome (IBS). The driving force for immune activation in IBS remains unknown. The aim of our study was to find out if the obligate intracellular pathogen Chlamydia could be involved in the pathogenesis of IBS.

METHODS

We studied 65 patients (61 females) with IBS and 42 (29 females) healthy controls in which IBS had been excluded. Full thickness biopsies from the jejunum and mucosa biopsies from the duodenum and the jejunum were stained with a monoclonal antibody to Chlamydia lipopolysaccharide (LPS) and species-specific monoclonal antibodies to C. trachomatis and C. pneumoniae. We used polyclonal antibodies to chromogranin A, CD68, CD11c, and CD117 to identify enteroendocrine cells, macrophages, dendritic, and mast cells, respectively.

RESULTS

Chlamydia LPS was present in 89% of patients with IBS, but in only 14% of healthy controls (p < 0.001) and 79% of LPS-positive biopsies were also positive for C. trachomatis major outer membrane protein (MOMP). Staining for C. pneumoniae was negative in both patients and controls. Chlamydia LPS was detected in enteroendocrine cells of the mucosa in 90% of positive biopsies and in subepithelial macrophages in 69% of biopsies. Biopsies taken at different time points in 19 patients revealed persistence of Chlamydia LPS up to 11 years. The odds ratio for the association of Chlamydia LPS with presence of IBS (43.1; 95% CI: 13.2-140.7) is much higher than any previously described pathogenetic marker in IBS.

CONCLUSIONS

We found C. trachomatis antigens in enteroendocrine cells and macrophages in the small bowel mucosa of patients with IBS. Further studies are required to clarify if the presence of such antigens has a role in the pathogenesis of IBS.

Detection of Chlamydia pneumoniae by polymerase chain reaction-enzyme immunoassay in intestinal mucosal biopsies from patients with inflammatory bowel disease and controls

BACKGROUND AND AIM

It has been suggested that Chlamydia is an organism that may have the potential to cause inflammatory bowel disease (IBD) in susceptible individuals. Chlamydia pneumoniae has emerged as an important human pathogen in the last decade. The objective of the present study was to investigate the frequency of the presence of C. pneumoniae DNA in intestinal biopsies from patients with IBD and from non-IBD controls.

METHODS

The DNA was extracted from 222 colonoscopic biopsies, which were obtained from 11 patients with Crohn's disease (CD), 18 patients with ulcerative colitis (UC) and from 37 non-IBD control patients. The presence of the C. pneumoniae omp1 gene and C. trachomatis 16S rRNA gene was determined using a rapid and sensitive polymerase chain reaction-enzyme immunoassay (PCR-EIA).

RESULTS

The C. pneumoniae-specific DNA was detected in 32 (14.4%) of 222 endoscopic biopsies. Among them, C. pneumoniae DNA were found in nine of 42 (21.4%) biopsies from patients with CD, nine of 59 (15.3%) biopsies from patients with UC, and 14 out of 122 (11.4%) biopsies from non-IBD control patients, respectively. Moreover, the percentage of patients with at least one biopsy positive for C. pneumoniae was higher, although not statistically significant, in CD (36.4%) and UC patients (38.9%) compared to non-IBD controls (16.2%). In contrast, C. trachomatis DNA was detected in only two of 222 (0.9%) biopsy samples.

CONCLUSION

The C. pneumoniae DNA was detected in the intestine of both patients with IBD and in non-IBD control patients, probably reflecting the high prevalence of this organism in the environment. The moderate yield of positive biopsies in our IBD patients and the fact that the detection rate of C. pneumoniae DNA was similar in endoscopic biopsies from IBD patients and non-IBD controls does not support a direct role for this organism in the pathogenesis of IBD.