Invasive Fusobacterium nucleatum species good markers of IBD status
MedWire News: Study findings show that invasive strains of Fusobacterium, bacteria commonly found in the human gut mucosa, are present in more patients with inflammatory bowel disease (IBD) than in healthy controls.
"The microflora of the gut is believed to be central in the development of both ulcerative colitis and Crohn's disease," explain Emma Allen-Vercoe (University of Guelph, Ontario, Canada) and colleagues.
However, "the complexity and diversity of the microflora of the human gut have made it difficult to pinpoint whether there are bacterial species that are specifically associated with IBD exacerbations," says the team.
For this study, the researchers obtained biopsy tissue from 56 adults who underwent colonoscopy for cancer- or gastrointestinal-disease screening purposes. Of these, 22 had IBD or indeterminate colitis (IC).
Fusobacterium nucleatum has previously been associated with inflammatory disease in the mouth and is commonly isolated from intestinal samples. To assess its role in IBD, Allen-Vercoe and co-workers tested the IBD/IC and control biopsy samples for the presence of different Fusobacterium strains.
They found that Fusobacterium species were isolated from significantly more IBD/IC patients than controls, at 63.6% versus 26.5%. Of these, 69% of the species overall were identified as being F. nucleatum, with 50% of IBD/IC and 17.6% of control samples containing this species.
The investigators used a Caco-2 cell invasion assay to test the invasive and proinflammatory properties of the isolated F. nucleatum strains. They found that the strains from the IBD/IC patients were significantly more invasive than those isolated from the healthy controls.
"This study indicates that colonization of the intestinal mucosa by highly invasive strains of F. nucleatum may be a useful biomarker for gastrointestinal disease," write the authors.
"The recent finding by Swidsinski et al that F. nucleatum is a potential cause of acute appendicitis suggests that F. nucleatum may be a previously underestimated pathogen in the gastrointestinal setting, and lends weight to our finding that recovery of highly invasive F. nucleatum strains from mucosal biopsy specimens is positively associated with the IBD status of the patient," they add.
The results of this study are published in the journal Inflammatory Bowel Diseases.
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By Helen Albert