Mucosal flora in inflammatory bowel disease.
OBJECTIVE
Microorganisms that directly interact with the intestinal mucosa are obscured by fecal flora and poorly characterized.


METHODS
We investigated the mucosal flora of washed colonoscopic biopsies of 305 patients with bowel inflammation and 40 controls. The microbial cultures were validated by quantitative polymerase chain reaction with subsequent cloning and sequencing, fluorescence in-situ hybridization, and electron microscopy.


RESULTS
We found high concentrations of mucosal bacteria in patients with bowel inflammation, but not in controls. The concentrations of mucosal bacteria increased progressively with the severity of disease, both in inflamed and non-inflamed colon. In patients with >10,000 cfu/microL, a thick bacterial band was attached to the intact mucosa without signs of translocation. Patients with inflammatory bowel disease (IBD) and concentrations of mucosal bacteria >50,000 cfu/microL had characteristic inclusions of multiple polymorphic bacteria within solitary enterocytes located next to the lamina propria, without or having no contact with the fecal stream. The identified bacteria were of fecal origin.


CONCLUSIONS
Our findings suggest that the changes in the mucosal flora in IBD are not secondary to inflammation, but a result of a specific host response. We hypothesize that the healthy mucosa is capable of holding back fecal bacteria and that this function is profoundly disturbed in patients with IBD.
Swidsinski
Alexander
A
Innere Klinik, Gastroenterologie, Charité Humboldt Universität, Berlin, Germany. alexander.swindinski@charite.de
Ladhoff
Axel
A
Pernthaler
Annelie
A
Swidsinski
Sonja
S
Loening-Baucke
Vera
V
Ortner
Marianne
M
Weber
Jutta
J
Hoffmann
Uwe
U
Schreiber
Stefan
S
Dietel
Manfred
M
Lochs
Herbert
H
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001431:Bacteriological Techniques; D001439:Bacteroides / Q000235:genetics / Q000302:isolation & purification*; D001442:Bacteroides Infections / Q000473:pathology*; D001706:Biopsy; D004269:DNA, Bacterial / Q000032:analysis; D004755:Enterobacteriaceae / Q000235:genetics / Q000302:isolation & purification*; D004756:Enterobacteriaceae Infections / Q000473:pathology*; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D015212:Inflammatory Bowel Diseases / Q000382:microbiology* / Q000473:pathology; D007413:Intestinal Mucosa / Q000382:microbiology* / Q000473:pathology / Q000648:ultrastructure; D008297:Male; D008854:Microscopy, Electron; D008875:Middle Aged; D016133:Polymerase Chain Reaction
D004269:DNA, Bacterial