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The intestinal microbiota is suspected to play a role in colitis and particularly in inflammatory bowel disease (IBD) pathogenesis. The aim was to compare the fecal microbiota composition of patients with colitis to that of healthy subjects (HS).Methodsfecal samples from 22 active Crohn's disease (A-CD) patients, 10 CD patients in remission (R-CD), 13 active ulcerative colitis (A-UC) patients, 4 UC patients in remission (R-UC), 8 infectious colitis (IC) patients, and 27 HS were analyzed by quantitative real-time polymerase chain reaction (PCR) targeting the 16S rRNA gene. Bacterial counts were transformed to logarithms (Log10 CFU) for statistical analysis.ResultsBacteria of the phylum Firmicutes (Clostridium leptum and Clostridium coccoides groups) were less represented in A-IBD patients (9.7; P = 0.004) and IC (9.4; P = 0.02), compared to HS (10.8). Faecalibacterium prausnitzii species (a major representative of the C. leptum group) had lower counts in A-IBD and IC patients compared to HS (8.8 and 8.3 versus 10.4; P = 0.0004 and P = 0.003). The Firmicutes/Bacteroidetes ratio was lower in A-IBD (1.3; P = 0.0001) and IC patients (0.4; P = 0.002). Compared to HS, Bifidobacteria were less represented in A-IBD and IC (7.9 and 7.7 versus 9.2; P = 0.001 and P = 0.01).ConclusionsThe fecal microbiota of patients with IBD differs from that of HS. The phylum Firmicutes and particularly the species F. prausnitzii, are underrepresented in A-IBD patients as well as in IC patients. These bacteria could be crucial to gut homeostasis since lower counts of F. prausnitzii are consistently associated with a reduced protection of the gut mucosa.

BackgroundCrohn’s disease (CD)-associated dysbiosis is characterised by a loss of Faecalibacterium prausnitzii, whose culture supernatant exerts an anti-inflammatory effect both in vitro and in vivo. However, the chemical nature of the anti-inflammatory compounds has not yet been determined.MethodsPeptidomic analysis using mass spectrometry was applied to F. prausnitzii supernatant. Anti-inflammatory effects of identified peptides were tested in vitro directly on intestinal epithelial cell lines and on cell lines transfected with a plasmid construction coding for the candidate protein encompassing these peptides. In vivo, the cDNA of the candidate protein was delivered to the gut by recombinant lactic acid bacteria to prevent dinitrobenzene sulfonic acid (DNBS)-colitis in mice.ResultsThe seven peptides, identified in the F. prausnitzii culture supernatants, derived from a single microbial anti-inflammatory molecule (MAM), a protein of 15 kDa, and comprising 53% of non-polar residues. This last feature prevented the direct characterisation of the putative anti-inflammatory activity of MAM-derived peptides. Transfection of MAM cDNA in epithelial cells led to a significant decrease in the activation of the nuclear factor (NF)-κB pathway with a dose-dependent effect. Finally, the use of a food-grade bacterium, Lactococcus lactis, delivering a plasmid encoding MAM was able to alleviate DNBS-induced colitis in mice.ConclusionsA 15 kDa protein with anti-inflammatory properties is produced by F. prausnitzii, a commensal bacterium involved in CD pathogenesis. This protein is able to inhibit the NF-κB pathway in intestinal epithelial cells and to prevent colitis in an animal model.

Background and aims: Early endoscopic recurrence is frequent after intestinal resection for Crohn’s disease. Bacteria are involved, and probiotics may modulate immune responses to the intestinal flora. Here we tested the probiotic strain Lactobacillus johnsonii LA1 in this setting. Patients and methods: This was a randomised, double blind, placebo controlled study. Patients were eligible if they had undergone surgical resection of <1 m, removing all macroscopic lesions within the past 21 days. Patients were randomised to receive two packets per day of lyophilised LA1 (2×109 cfu) or placebo for six months; no other treatment was allowed. The primary endpoint was endoscopic recurrence at six months, with grade >1 in Rutgeerts’ classification or an adapted classification for colonic lesions. Endoscopic score was the maximal grade of ileal and colonic lesions. Analyses were performed primarily on an intent to treat basis. Results: Ninety eight patients were enrolled (48 in the LA1 group). At six months, endoscopic recurrence was observed in 30/47 patients (64%) in the placebo group and in 21/43 (49%) in the LA1 group (p = 0.15). Per protocol analysis confirmed this result. Endoscopic score distribution did not differ significantly between the LA1 and placebo groups. There were four clinical recurrences in the LA1 group and three in the placebo group. Conclusion:L johnsonii LA1 (4×109 cfu/day) did not have a sufficient effect, if any, to prevent endoscopic recurrence of Crohn’s disease.

Probiotics are viable non-pathogenic micro-organisms which, when ingested, exert a positive influence on host health or physiology. We have critically analysed the evidence for the efficacy of specific probiotic strains in human gastrointestinal diseases. The best evidence can be obtained with randomised controlled trials which avoid bias. Good evidence has been obtained with several strains in the prevention or treatment of antibiotic-associated disorders, in the treatment (and to a lesser extent prevention) of gastroenteritis and acute diarrhoea and in the alleviation of lactose intolerance. We also analysed the recent randomised controlled trials performed in patients with Clostridium difficile or Helicobacter pylori, inflammatory bowel disease, irritable bowel syndrome, non-ulcer dyspepsia and colon cancer.

Rescue therapy with either cyclosporine (CYS) or infliximab (IFX) is an effective option in patients with intravenous steroid-refractory attacks of ulcerative colitis (UC). In patients who fail, colectomy is usually recommended, but a second-line rescue therapy with IFX or CYS is an alternative. The aims of this study were to investigate the efficacy and tolerance of IFX and CYS as a second-line rescue therapy in steroid-refractory UC or indeterminate colitis (IC) unsuccessfully treated with CYS or IFX. This was a retrospective survey of patients seen during the period 2000-2008 in the GETAID centers. Inclusion criteria included a delay of <1 month between CYS withdrawal (when used first) and IFX, or a delay of <2 months between IFX (when used first) and CYS, and a follow-up of at least 3 months after inclusion. Time-to-colectomy, clinical response, and occurrence of serious adverse events were analyzed. A total of 86 patients (median age 34 years; 49 males; 71 UC and 15 IC) were successively treated with CYS and IFX. The median (± s.e.) follow-up time was 22.6 (7.0) months. During the study period, 49 patients failed to respond to the second-line rescue therapy and underwent a colectomy. The probability of colectomy-free survival (± s.e.) was 61.3 ± 5.3% at 3 months and 41.3 ± 5.6 % at 12 months. A case of fatal pulmonary embolism occurred at 1 day after surgery in a 45-year-old man. Also, nine infectious complications were observed during the second-line rescue therapy. In patients with intravenous steroid-refractory UC and who fail to respond to CYS or IFX, a second-line rescue therapy may be effective in carefully selected patients, avoiding colectomy within 2 months in two-thirds of them. The risk/benefit ratio should still be considered individually.

Aim: To assess the characteristics and clinical course of nodular regenerative hyperplasia (NRH) in patients with inflammatory bowel disease treated with azathioprine, so as to estimate the frequency of this complication and search for risk factors. Methods: Cases were identified through a systematic survey of patients followed at 11 centres. At one centre, the cumulative risk of NRH was estimated and a case–control study was undertaken to identify risk factors. Results: 37 cases of NRH (30 male, 7 female) were identified between 1994 and 2005. The median dose of azathioprine was 2 mg/kg/d (range 1.5 to 3.0). The median time between the start of azathioprine and the diagnosis of NRH was 48 months (range 6 to 187). After a median follow up period of 16 months (range 1 to 138), 14 patients developed complications of portal hypertension. Using multivariate analysis, male sex and stricturing behaviour were the two risk factors associated with NRH in patients treated with azathioprine. The cumulative risk calculated from the database (one centre) was 0.5% at 5 years (95% confidence interval, 0.11 to 0.89) and 1.25% at 10 years (0.29 to 2.21). Conclusions: NRH is a rare but potentially severe complication of azathioprine in patients with inflammatory bowel disease. Clinicians should be aware of this complication, and should monitor liver function tests and platelet counts closely in their patients.

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.

BACKGROUND: The mucosa-associated microbiota, being very close to the inflammatory process associated with inflammatory bowel disease (IBD), may have a pathogenic role. We used a culture-independent method to analyze the mucosa-associated microbiota in IBD patients at various points of the distal digestive tract. METHODS: Thirty-five patients (20 with Crohn's disease, 11 with ulcerative colitis, and 4 controls) underwent colonoscopy. Biopsies (n = 126) were taken from 4 sites: the ileum, right colon, left colon, and rectum. Fecal samples were also obtained from 7 individuals. Temporal temperature gradient gel electrophoresis (TTGE) of 16S rDNA was used to evaluate dominant species diversity. TTGE profiles were compared using software that measures the degree of similarity. RESULTS: In a given individual, the overall similarity percentage between the 4 segments of the distal digestive tract was 94.7 +/- 4.0%, regardless of clinical status. The average similarity of all profiles for a given segment was 59.3 +/- 18.3% in the overall population. Dendrogram analysis showed that TTGE profiles did not cluster with clinical status. Differences were observed between the dominant fecal microbiota and the mucosa-associated microbiota of all 4 sites, with similarity percentages less than 92%. CONCLUSIONS: These results confirm that the dominant species differ between the mucosa-associated and fecal microbiota. They also show that, in a given individual, the microbiota is relatively stable along the distal digestive tract, showing a slight evolution in dominant species diversity from the ileum to the rectum, in both healthy subjects and patients with IBD.

A decrease in the abundance and biodiversity of intestinal bacteria within the dominant phylum Firmicutes has been observed repeatedly in Crohn disease (CD) patients. In this study, we determined the composition of the mucosa-associated microbiota of CD patients at the time of surgical resection and 6 months later using FISH analysis. We found that a reduction of a major member of Firmicutes, Faecalibacterium prausnitzii, is associated with a higher risk of postoperative recurrence of ileal CD. A lower proportion of F. prausnitzii on resected ileal Crohn mucosa also was associated with endoscopic recurrence at 6 months. To evaluate the immunomodulatory properties of F. prausnitzii we analyzed the anti-inflammatory effects of F. prausnitzii in both in vitro (cellular models) and in vivo [2,4,6-trinitrobenzenesulphonic acid (TNBS)-induced] colitis in mice. In Caco-2 cells transfected with a reporter gene for NF-κB activity, F. prausnitzii had no effect on IL-1β-induced NF-κB activity, whereas the supernatant abolished it. In vitro peripheral blood mononuclear cell stimulation by F. prausnitzii led to significantly lower IL-12 and IFN-γ production levels and higher secretion of IL-10. Oral administration of either live F. prausnitzii or its supernatant markedly reduced the severity of TNBS colitis and tended to correct the dysbiosis associated with TNBS colitis, as demonstrated by real-time quantitative PCR (qPCR) analysis. F. prausnitzii exhibits anti-inflammatory effects on cellular and TNBS colitis models, partly due to secreted metabolites able to block NF-κB activation and IL-8 production. These results suggest that counterbalancing dysbiosis using F. prausnitzii as a probiotic is a promising strategy in CD treatment.

Diagnosis of Meckel's diverticulum was proposed and a Technetium-99 m pertechnetate scan was then performed and confirmed the diagnosis, showing a focal signal in the lower part of the abdomen due to the presence of ectopic gastric mucosa ( fig 1 ).