Crypt abscess-associated microbiota in inflammatory bowel disease and acute self-limited colitis.

AIM To evaluate whether crypt abscesses from inflammatory bowel disease (IBD) patients contain bacteria and to establish their nature. METHODS We studied 17 ulcerative colitis patients, 11 Crohn's disease patients, 7 patients with acute self-limited colitis (ASLC) and normal colonic biopsies from 5 subjects who underwent colonoscopy for colon cancer screening. A fluorescent in situ hybridization technique was applied to colonic biopsies to assess the microbiota composition of the crypts and crypt abscesses. RESULTS Crypts colonized by bacteria were observed in 42.9% and 3.6% of ASLC and IBD patients, respectively (P = 0.019). Crypt abscesses colonized by bacteria were observed in 28.6% and 0.0% of ASLC and IBD patients, respectively (P = 0.035). CONCLUSION These results do not support the hypothesis that crypt abscesses in IBD are the result of localized dysbiosis arising from persistence of living bacteria colonizing the crypts.