Alterations of the dominant faecal bacterial groups in patients with Crohn's disease of the colon

Abstract

Background and aim: The colonic microflora is involved in the pathogenesis of Crohn's disease (CD) but less than 30% of the microflora can be cultured. We investigated potential differences in the faecal microflora between patients with colonic CD in remission (n=9), patients with active colonic CD (n=8), and healthy volunteers (n=16) using culture independent techniques. Methods: Quantitative dot blot hybridisation with six radiolabelled 16S ribosomal ribonucleic acid (rRNA) targeting oligonucleotide probes was used to measure the proportions of rRNA corresponding to each phylogenetic group. Temporal temperature gradient gel electrophoresis (TTGE) of 16S rDNA was used to evaluate dominant species diversity. Results: Enterobacteria were significantly increased in active and quiescent CD. Probe additivity was significantly lower in patients (65 (11)% and 69 (6)% in active CD and quiescent CD) than in healthy controls (99 (7)%). TTGE profiles varied markedly between active and quiescent CD but were stable in healthy conditions. Conclusion: The biodiversity of the microflora remains high in patients with CD. Enterobacteria were observed significantly more frequently in CD than in health, and more than 30% of the dominant flora belonged to yet undefined phylogenetic groups.

Gram-Negative Bacteria Aggravate Murine Small Intestinal Th1-Type Immunopathology following Oral Infection with Toxoplasma gondii

“…IBD patients display immunoreactivity against bacterial Ags (10 -12) and intestinal immunopathology is accompanied by accumulation of Escherichia coli or Bacteroides spp. at inflamed tissue sites (13)(14)(15)(16). In experimental colitis (17)(18)(19)(20)(21)(22)(23)(24), inflammation was suppressed in germfree animals or animals treated with antibiotics.…”

Molecular analysis of the gut microbiota of identical twins with Crohn's disease

“…Previous studies have found that the microbial diversity in the gut is lower in individuals with CD compared to healthy individuals (Seksik et al, 2003;Manichanh et al, 2006;Scanlan et al, 2006). For example, there have been reports of a reduced diversity of Firmicutes (Gophna et al, 2006;Manichanh et al, 2006) and Bacteroides (Ott et al, 2004;Frank et al, 2007) in CD patients.…”

“…are dominant members of the fecal microbiota (Seksik et al, 2003;Ott et al, 2004;Scanlan et al, 2006) and our Bacteroides clone sequences from the same material had the same TRF sizes (see below). Therefore, a group-specific primer set was used during T-RFLP, to focus on the Bacteroides group in the same DNA extracts from the fecal samples that were previously analyzed using general bacterial primers.…”

Human gut microbiota: does diet matter?

“…Under normal circumstances, predominant intestinal microbiota of an adult individual is fairly stable. However, in studies where the long-term temporal stability of the predominant microbiota has been assessed from healthy subjects, the number of subjects has been limited (13)(14)(15)(16) . The human GI-tract, although harbouring a vast number of microbes, has only a limited diversity at the phylum level.…”