Mucocutaneous manifestations of inflammatory bowel disease.

Mucocutaneous manifestations can be indicative of a variety of gastrointestinal diseases, and the dermatologist needs to know how to recognize them to refer the right patients to the gastroenterologist. Conversely, the gastroenterologist is often confronted with mucocutaneous lesions that raise the question of a possible association with a known digestive disease. Among the extra-intestinal manifestations of inflammatory bowel disease (IBD), mucocutaneous manifestations are the most common. This review will provide a breakdown by classifying them into 4 groups: 1) reactive manifestations, which include neutrophilic dermatoses, aphthous stomatitis, erythema nodosum, and vasculitis; 2) Crohn's disease-specific granulomatous skin lesions, which are histologically characterized by tuberculoid granulomas similar to those found in the gastrointestinal tract; 3) nutritional deficiency manifestations secondary to anorexia, malabsorption, loss, and drug interactions; and 3) a variety of autonomous autoimmune or inflammatory skin diseases. Dermatologists may also be involved in the management of the adverse effects of IBD treatments, especially the so-called "paradoxical" psoriatic eruptions.

Influence of Early Life Factors, including breast milk Composition, on the Microbiome of Infants Born to Mothers with and without Inflammatory Bowel Disease.

BACKGROUND AND AIMS: Herein we analysed the influence of early life factors, including breast milk composition, on the development of the intestinal microbiota of infants born to mothers with and without IBD. METHODS: The MECONIUM [Exploring MEChanisms Of disease traNsmission In Utero through the Microbiome] study is a prospective cohort study consisting of pregnant women with or without IBD and their infants. Longitudinal stool samples were collected from babies and analysed using 16s rRNA sequencing and faecal calprotectin. Breast milk proteomics was profiled using Olink inflammation panel. RESULTS: We analysed gut microbiota of 1034 faecal samples from 294 infants [80 born to mothers with and 214 to mothers without IBD]. Alpha diversity was driven by maternal IBD status and time point. The major influencers of the overall composition of the microbiota were mode of delivery, feeding, and maternal IBD status. Specific taxa were associated with these exposures, and maternal IBD was associated with a reduction in Bifidobacterium. In 312 breast milk samples [91 from mothers with IBD], mothers with IBD displayed lower abundance of proteins involved in immune regulation, such as thymic stromal lymphopoietin, interleukin-12 subunit beta, tumour necrosis factor-beta, and C-C motif chemokine 20, as compared with control mothers [adjusted p = 0.0016, 0.049, 0.049, and 0.049, respectively], with negative correlations with baby´s calprotectin, and microbiome at different time points. CONCLUSION: Maternal IBD diagnosis influences microbiota in their offspring during early life. The proteomic profile of breast milk of women with IBD differs from that of women without IBD, with distinct time-dependent associations with baby's gut microbiome and feacal calprotectin.

Long-term efficacy and safety of ustekinumab for Crohn's disease through the second year of therapy.

BACKGROUND: In Phase 3 studies of ustekinumab, a fully human monoclonal IL-12/23p40 antibody approved for moderate-to-severe Crohn's disease, patients entered a long-term extension after completing 8 weeks of induction and 44 weeks of maintenance treatment. Efficacy through 92 weeks and safety through 96 weeks of IM-UNITI maintenance are reported. METHODS: UNITI-1 (TNF-antagonist failures) and UNITI-2 (conventional therapy failures) patients (N = 1281) entered IM-UNITI, including 397 ustekinumab intravenous induction responders randomised to subcutaneous ustekinumab 90 mg every 12 weeks, every 8 weeks, or placebo and 884 nonrandomised patients. Dose-adjustment to 90 mg every 8 weeks occurred in patients randomised to 90 mg every 12 weeks and placebo patients with loss of response (Weeks 8-32). All Week 44 completers could enter the long-term extension without further dose adjustment. Placebo patients discontinued following study unblinding. RESULTS: A total of 718 patients (all treated) entered the long-term extension (298 randomised and 420 not randomised). Overall, 86.5% (621/718) completed Week 96. The proportions of randomised patients in clinical remission were generally maintained from Week 44 through 92 in ustekinumab 90 mg every 12 weeks (77.4% to 72.6%), every 8 weeks (84.1% to 74.4%), and prior dose adjustment groups (63.4% to 53.5%). At Week 92, the proportions of patients in clinical remission were similar in the ustekinumab 90 mg every 12 weeks and every 8 weeks groups and lower in patients with prior dose adjustment. Proportions of patients in clinical remission at Week 92 for all treated every 8 weeks (64.4%) and every 12 weeks (64.3%) groups were lower than randomised every 8 weeks (74.4%) and every 12 weeks (72.6%) groups, but similarly maintained. Safety events (per hundred patient-years) were similar among all placebo and ustekinumab patients (Week 0-96), including adverse events (484.39 vs 447.76), serious adverse events (19.24 vs 18.82), and serious infections (4.09 vs 4.02). No dose effect was observed. CONCLUSIONS: Subcutaneous ustekinumab maintained clinical response and remission through Week 92. No new safety signals were observed. ClinicalTrials.gov number NCT01369355.

Bariatric surgery is associated with increased risk of new-onset inflammatory bowel disease: case series and national database study.

BACKGROUND: Case series suggest a possible association between bariatric surgery and incident IBD. AIM: The aim of this study was to evaluate the association between bariatric surgery and new-onset IBD. METHODS: We first conducted a multi-institutional case series of patients with a history of IBD and bariatric surgery. We next conducted a matched case-control study using medical and pharmacy claims from 2008 to 2012 in a US national database from Source Healthcare Analytics LLC. Bariatric surgery was defined by ICD-9 or CPT code. Bariatric surgery was evaluated as recent (code in database timeframe), past (past history V code) or no history. Conditional logistic regression was used to estimate odds ratios (OR) and 95% CI for new-onset IBD, CD and UC. RESULTS: A total of 15 cases of IBD (10 CD, 4 UC, 1 IBD, type unclassified) with a prior history of bariatric surgery were identified. Most cases were women, had Roux-en-Y surgery years prior to diagnosis and few IBD-related complications. A total of 8980 cases and 43 059 controls were included in our database analysis. Adjusting for confounders, a past history of bariatric surgery was associated with an increased risk of new-onset IBD (OR 1.93, 95% CI 1.34-2.79). However, patients who had recent bariatric surgery did not appear to be at shorter term risk of IBD (OR 0.94, 95% CI 0.58-1.52). CONCLUSION: New-onset IBD was significantly associated with a past history of bariatric surgery. This potential association needs to be confirmed in future prospective studies.

The gut microbiota, bile acids and their correlation in primary sclerosing cholangitis associated with inflammatory bowel disease.

BACKGROUND: Patients with primary sclerosing cholangitis associated with inflammatory bowel disease (PSC-IBD) have a very high risk of developing colorectal neoplasia. Alterations in the gut microbiota and/or gut bile acids could account for the increase in this risk. However, no studies have yet investigated the net result of cholestasis and a potentially altered bile acid pool interacting with a dysbiotic gut flora in the inflamed colon of PSC-IBD. AIM: The aim of this study was to compare the gut microbiota and stool bile acid profiles, as well as and their correlation in patients with PSC-IBD and inflammatory bowel disease alone. METHODS: Thirty patients with extensive colitis (15 with concomitant primary sclerosing cholangitis) were prospectively recruited and fresh stool samples were collected. The microbiota composition in stool was profiled using bacterial 16S rRNA sequencing. Stool bile acids were assessed by high-performance liquid chromatography tandem mass spectrometry. RESULTS: The total stool bile acid pool was significantly reduced in PSC-IBD. Although no major differences were observed in the individual bile acid species in stool, their overall combination allowed a good separation between PSC-IBD and inflammatory bowel disease. Compared with inflammatory bowel disease alone, PSC-IBD patients demonstrated a different gut microbiota composition with enrichment in Ruminococcus and Fusobacterium genus compared with inflammatory bowel disease. At the operational taxonomic unit level major shifts were observed within the Firmicutes (73%) and Bacteroidetes phyla (17%). Specific microbiota-bile acid correlations were observed in PSC-IBD, where 12% of the operational taxonomic units strongly correlated with stool bile acids, compared with only 0.4% in non-PSC-IBD. CONCLUSIONS: Patients with PSC-IBD had distinct microbiota and microbiota-stool bile acid correlations as compared with inflammatory bowel disease. Whether these changes are associated with, or may predispose to, an increased risk of colorectal neoplasia needs to be further clarified.

Review article: predictors of response to vedolizumab and ustekinumab in inflammatory bowel disease.

BACKGROUND: Increased knowledge of pathways involved in the pathogenesis of IBD has led to the development of new treatment options for Crohn's disease (CD) and ulcerative colitis (UC). Two new biological agents have been recently approved for IBD: vedolizumab and ustekinumab. They have different therapeutic targets (α4 ß7 integrin for vedolizumab and interleukin-12/23 pathways for ustekinumab) than the primary biological class, anti-tumour necrosis factor alpha (anti-TNF) agents. As the armamentarium for IBD increases in coming years, it will become important to understand factors associated with response in order to best position and personalise therapy. AIM: To summarise the current data on predictors of response to vedolizumab and ustekinumab in IBD patients. METHODS: We conducted a comprehensive literature review. A PubMed search was performed using pre-defined key words and terms to identify relevant studies on predictors of response. RESULTS: Patients with severe disease (by clinical activity and inflammatory biomarkers), or prior anti-TNF exposure are less likely to respond to vedolizumab. Ileocolonic disease, no prior surgery and uncomplicated phenotype were associated with better responses to ustekinumab in CD. Initial response seems to predict a better long-term maintenance in both therapies (P < 0.001). Contrary to anti-TNF therapies, immunogenicity appears to play less of a role in response. CONCLUSION: As the number of new biological therapies increase in IBD, identifying patients who are most likely to benefit from specific agents is of paramount importance to help best position IBD therapies.

Long-term safety of adalimumab in clinical trials in adult patients with Crohn's disease or ulcerative colitis.

BACKGROUND: Adalimumab is used to treat moderate to severe Crohn's disease (CD) and ulcerative colitis (UC) when conventional therapies fail. AIM: To update long-term adalimumab safety from CD and UC trials; the previous report was CD only, 3160 patients/3402 patient-years (PYs). METHODS: Treatment-emergent adverse events (AEs; first dose to 70 days after last dose/December 31, 2015) in adults in phase 2/3 and 3/3b trials and open-label extensions were coded using Medical Dictionary for Regulatory Activities (MedDRA-v18.1). Rates were assessed as events/100 (E/100 PYs). RESULTS: The database (16 trials; CD, N = 3606; UC, N = 1739) represented 4145 and 3397 PYs of exposure, respectively. For CD, incidences of any AEs with adalimumab were 60.8%-65.1%, depending on dose, and 71.5% with placebo; for UC, the incidences were 53.5%-54.8% and 56.1%, respectively. Rates of any AEs (CD, 605 E/100 PYs; UC, 361 E/100 PYs), serious AEs (CD, 36.1 E/100 PYs; UC, 18.9 E/100 PYs), and malignancies (CD, 1.2 E/100 PYs; UC, 1.0 E/100 PYs) were similar between current and prior analyses. Apparent rate of opportunistic infections was lowered to 0.3 and 0.2 E/100 PYs for CD and UC, respectively, by recent MedDRA changes excluding oral candidiasis and tuberculosis. Standardised incidence ratios for malignancies were similar to the general population (CD, 1.45 [95% CI, 0.90-2.22]; UC, 1.36 [95% CI, 0.84-2.07]). Demyelinating disorders were uncommon (CD, 0.1 E/100 PYs; UC, <0.1 E/100 PYs). CONCLUSIONS: Patients with moderately to severely active Crohn's disease or ulcerative colitis continued to experience acceptable safety with adalimumab, without new safety signals.

Effects of concomitant immunomodulators on the pharmacokinetics, efficacy and safety of adalimumab in patients with Crohn's disease or ulcerative colitis who had failed conventional therapy.

BACKGROUND: Adalimumab is approved for use in patients with moderate to severe Crohn's disease (CD) or ulcerative colitis (UC) who have not achieved disease control with conventional therapies including corticosteroids and/or immunomodulators (IMM). AIM: To analyse six studies that examined efficacy, pharmacokinetics and safety of combination IMM/adalimumab therapy, compared with adalimumab monotherapy in patients with inadequate disease control on conventional therapy. METHODS: Patients with moderate to severe CD or UC from randomised, double-blind, placebo-controlled trials were analysed. Adalimumab was added to background therapy; patients were categorised as receiving adalimumab monotherapy (CD induction, n = 245, maintenance, n = 185; UC induction, n = 213, maintenance, n = 157) or combination therapy (CD induction, n = 139, maintenance, n = 139; UC induction, n = 140, maintenance, n = 100) according to baseline immunomodulator use. Efficacy was reported for the intent-to-treat populations from each study, with remission defined as CD activity index <150 for CD and Mayo score ≤2 with no subscore >1 for UC. Safety was assessed via adverse events. RESULTS: The proportions of patients achieving remission were similar for adalimumab monotherapy and immunomodulator combination therapy in all studies. Median adalimumab concentrations at week 4 or 8 were numerically but not significantly higher with adalimumab combination therapy vs. monotherapy in the CD and UC studies respectively. Incidence and rate of adverse events was similar for adalimumab monotherapy and combination therapy. CONCLUSIONS: Post hoc analysis of six randomised, controlled trials demonstrated no efficacy benefits with immunomodulator/adalimumab combination therapy, compared with adalimumab monotherapy in CD and UC patients with inadequate disease control on conventional therapy; the safety of the two treatment approaches was comparable.

Effects of vedolizumab on health-related quality of life in patients with ulcerative colitis: results from the randomised GEMINI 1 trial.

BACKGROUND: Health-related quality of life (HRQL) is often diminished in patients with ulcerative colitis. AIM: To evaluate the effects of vedolizumab on HRQL in patients with ulcerative colitis. METHODS: Using maintenance phase data from the GEMINI 1 study, an analysis of covariance model was used to calculate mean differences between the vedolizumab and placebo groups in changes from baseline to week 52 for 3 HRQL instruments: The Inflammatory Bowel Disease Questionnaire (IBDQ), 36-Item Short Form Health Survey (SF-36), and EQ-5D. Proportions of patients meeting minimal clinically important difference (MCID) thresholds for changes on these instruments were compared between treatment groups for the overall population and for clinically important subgroups. Concordance between clinical remission and remission defined using IBDQ scores was examined. RESULTS: Compared with placebo-treated patients, vedolizumab-treated patients had greater improvements (152-201%) in IBDQ, EQ-5D visual analogue scale (VAS), and EQ-5D utility scores. Greater proportions (6.9-19.9%) of vedolizumab-treated patients than placebo-treated patients met MCID thresholds for all the instruments. Vedolizumab-treated patients with lower baseline disease activity and those without prior tumour necrosis factor (TNF) antagonist failure had greater HRQL improvements. Among 127 patients with clinical remission based on complete Mayo Clinic scores, >80% also had IBDQ remission; >70% of the 150 patients with IBDQ remission demonstrated clinical remission. CONCLUSIONS: Vedolizumab therapy was associated with significant improvements in HRQL measures compared with placebo. Benefits were greater in patients with lower disease activity and no prior TNF antagonist failure.

The effects of aminosalicylates or thiopurines on the risk of colorectal cancer in inflammatory bowel disease.

BACKGROUND: Whether aminosalicylates or thiopurines reduce the risk of colorectal cancer (CRC) in inflammatory bowel (IBD) disease is controversial. AIM: To assess simultaneously the chemopreventive effect of aminosalicylates or thiopurines in a case-control study nested in the CESAME observational cohort that enrolled consecutive patients with IBD between May 2004 and June 2005. Patients were followed up to December 2007. METHODS: Study population comprised 144 case patients who developed CRC from the diagnosis of IBD (65 and 79 cases diagnosed, respectively, before and from 2004, starting year of the prospective observational period of CESAME) and 286 controls matched for gender, age, IBD subtype and year of diagnosis, and cumulative extent of colitis. Exposure to aminosalicylates or thiopurines was defined by an exposure to the treatment during the year of the diagnosis of cancer. The propensity of receiving 5-ASA and thiopurines was quantified by a composite score taking into account patient and IBD characteristics. The role of aminosalicylates or thiopurines was assessed by multivariate analysis. Propensity scores and the history of primary sclerosing cholangitis were entered into the multivariate model for adjustment. RESULTS: By multivariate analysis adjusted for propensity, a significant protective effect of exposure to drugs during the year of cancer was found for aminosalicylates (OR = 0.587, 95% CI: 0.367-0.937, P = 0.0257), but not for thiopurines (OR = 0.762, 95% CI: 0.432-1.343, P = 0.3468). CONCLUSION: In a case-control study nested in the CESAME cohort, a significant decrease in the risk of colorectal cancer in IBD was associated with exposure to aminosalicylates, not to thiopurines.

Bacteriome and Mycobiome Interactions Underscore Microbial Dysbiosis in Familial Crohn's Disease.

UNLABELLED: Crohn's disease (CD) results from a complex interplay between host genetic factors and endogenous microbial communities. In the current study, we used Ion Torrent sequencing to characterize the gut bacterial microbiota (bacteriome) and fungal community (mycobiome) in patients with CD and their nondiseased first-degree relatives (NCDR) in 9 familial clusters living in northern France-Belgium and in healthy individuals from 4 families living in the same area (non-CD unrelated [NCDU]). Principal component, diversity, and abundance analyses were conducted, and CD-associated inter- and intrakingdom microbial correlations were determined. Significant microbial interactions were identified and validated using single- and mixed-species biofilms. CD and NCDR groups clustered together in the mycobiome but not in the bacteriome. Microbiotas of familial (CD and NCDR) samples were distinct from those of nonfamilial (NCDU) samples. The abundance of Serratia marcescens and Escherichia coli was elevated in CD patients, while that of beneficial bacteria was decreased. The abundance of the fungus Candida tropicalis was significantly higher in CD than in NCDR (P = 0.003) samples and positively correlated with levels of anti-Saccharomyces cerevisiae antibodies (ASCA). The abundance of C. tropicalis was positively correlated with S. marcescens and E. coli, suggesting that these organisms interact in the gut. The mass and thickness of triple-species (C. tropicalis plus S. marcescens plus E. coli) biofilm were significantly greater than those of single- and double-species biofilms. C. tropicalis biofilms comprised blastospores, while double- and triple-species biofilms were enriched in hyphae. S. marcescens used fimbriae to coaggregate or attach with C. tropicalis/E. coli, while E. coli was closely apposed with C. tropicalis Specific interkingdom microbial interactions may be key determinants in CD. IMPORTANCE: Here, we characterized the gut bacterial microbiota (bacteriome) and fungal community (mycobiome) in multiplex families with CD and healthy relatives and defined the microbial interactions leading to dysbiosis in CD. We identified fungal (Candida tropicalis) and bacterial (Serratia marcescens and Escherichia coli) species that are associated with CD dysbiosis. Additionally, we found that the level of anti-Saccharomyces cerevisiae antibodies (ASCA; a known CD biomarker) was associated with the abundance of C. tropicalis We also identified positive interkingdom correlations between C. tropicalis, E. coli, and S. marcescens in CD patients and validated these correlations using in vitro biofilms. These results provide insight into the roles of bacteria and fungi in CD and may lead to the development of novel treatment approaches and diagnostic assays.

Serologic microbial associated markers can predict Crohn's disease behaviour years before disease diagnosis.

BACKGROUND: Patients with Crohn's disease (CD) have serologic responses to various microbial antigens. Serologic markers are associated with aggressive forms of disease and can be detected before onset of symptoms. Their utility in pre-clinical disease or prediction of complicated disease course before diagnosis is unclear. AIM: To evaluate the pattern of serologic anti-microbial antibodies long prior to diagnosis and the subsequent risk of complicated Crohn's disease at diagnosis. METHODS: Sera from 100 US military personnel with Crohn's disease were obtained from the Department of Defense Serum Repository. For each patient, four samples were obtained at different time points before and around diagnosis, and were tested for 6 microbiota-directed antibodies (ASCA-IgA, ASCA-IgG, anti-OmpC, anti-CBir1, anti-A4-Fla2 and anti-FlaX). Associations between the presence and accumulation of Crohn's disease anti-microbial antibodies before diagnosis and with the later development of complications were evaluated. RESULTS: Overall, 65 patients were positive for at least one Crohn's disease associated anti-microbial antibody in the earliest available sample, at a median of 6 years before Crohn's disease diagnosis (interquartile range, 5.6-8.2). The number of positive anti-microbial antibodies increased up to the time of Crohn's disease diagnosis. Complicated disease developed around the time of diagnosis in 24 patients. The proportion of positive antimicrobial antibodies before diagnosis was higher in patients with complicated vs. noncomplicated Crohn's disease. There was an inverse relationship between the time to first complication and the magnitude of serologic response before diagnosis. CONCLUSION: The presence and accumulation of circulating anti-microbial antibodies years before Crohn's disease diagnosis was associated with complicated Crohn's disease at or shortly after diagnosis.

The features of mucosa-associated microbiota in primary sclerosing cholangitis.

BACKGROUND: Little is known about the role of the microbiome in primary sclerosing cholangitis. AIM: To explore the mucosa-associated microbiota in primary sclerosing cholangitis (PSC) patients across different locations in the gut, and to compare it with inflammatory bowel disease (IBD)-only patients and healthy controls. METHODS: Biopsies from the terminal ileum, right colon, and left colon were collected from patients and healthy controls undergoing colonoscopy. Microbiota profiling using bacterial 16S rRNA sequencing was performed on all biopsies. RESULTS: Forty-four patients were recruited: 20 with PSC (19 with PSC-IBD and one with PSC-only), 15 with IBD-only and nine healthy controls. The overall microbiome profile was similar throughout different locations in the gut. No differences in the global microbiome profile were found. However, we observed significant PSC-associated enrichment in Barnesiellaceae at the family level, and in Blautia and an unidentified Barnesiellaceae at the genus level. At the operational taxa unit level, most shifts in PSC were observed in Clostridiales and Bacteroidales orders, with approximately 86% of shifts occurring within the former order. CONCLUSIONS: The overall microbiota profile was similar across multiple locations in the gut from the same individual regardless of disease status. In this study, the mucosa associated-microbiota of patients with primary sclerosing cholangitis was characterised by enrichment of Blautia and Barnesiellaceae and by major shifts in operational taxa units within Clostridiales order.

Excess risk of urinary tract cancers in patients receiving thiopurines for inflammatory bowel disease: a prospective observational cohort study.

BACKGROUND: The risk of urinary tract cancers, including kidney and bladder cancers, was increased in transplant recipients receiving thiopurines. AIM: To assess the risk of urinary tract cancers in patients with inflammatory bowel disease (IBD) receiving thiopurines in the CESAME observational cohort. METHODS: Between May 2004 and June 2005, 19 486 patients with IBD, 30.1% of whom were receiving thiopurines, were enrolled. Median follow-up was 35 months (IQR: 29-40). RESULTS: Ten and six patients developed respectively kidney and bladder cancer. The incidence rates of urinary tract cancer were 0.48/1000 patient-years in patients receiving thiopurines (95% CI: 0.21-0.95), 0.10/1000 patient-years in patients who discontinued thiopurines (95% CI: 0.00-0.56) and 0.30/1000 patient-years in patients never treated with thiopurines (95% CI: 0.12-0.62) at entry. The standardised incidence ratio of urinary tract cancer was 3.40 (95% CI: 1.47-6.71, P = 0.006) in patients receiving thiopurines, 0.64 (95% CI: 0.01-3.56, P = 0.92) in patients previously exposed to thiopurines and 1.17 (95% CI: 0.47-12.42, P = 0.78) in patients never treated with thiopurines. The multivariate-adjusted hazard ratio (HR) of urinary tract cancer between patients receiving thiopurines and those not receiving thiopurines was 2.82 (95% CI: 1.04-7.68, P = 0.04). Other significant risk factors were male gender (HR: 3.98, 95% CI: 1.12-14.10, P = 0.03) and increasing age (HR after 65 years (ref <50): 13.26, 95% CI: 3.52-50.03, P = 0.0001). CONCLUSION: Patients with IBD receiving thiopurines have an increased risk of urinary tract cancers. Clinically relevant excess risk is observed in older men.

Structural robustness of the gut mucosal microbiota is associated with Crohn's disease remission after surgery.

OBJECTIVES: Preventing postoperative recurrence after ileocolonic resection (ICR) for Crohn's disease (CD) is challenging. Defining the disturbances of the microbial composition and community structure after ICR and their link with early disease recurrence is crucial. DESIGN: Microbiota composition (fingerprinting and 16S rDNA sequencing) and community structure (correlation networks of bacterial species) were assessed from ileal mucosa sampled in 20 patients undergoing ICR and 6 months later during endoscopy from above (neoterminal ileum) and below (subanastomotic colon) the surgical anastomosis. RESULTS: ICR had a dramatic effect on gut microbial ecosystem. At surgery, CD mucosa harboured a dysbiotic microbiota with high proportions of α/ß Proteobacteria and Bacilli. Six months later, half of the patients had recurrent lesions at ileocolonoscopy and presented higher numbers of Lachnospiraceae. Recurrence of endoscopic lesions was associated with enrichment in Enterococcus durans while patients in remission had increased proportions of Dorea longicatena and Bacteroides plebeius. Structural differences were striking between recurrence and remission microbiota; while the microbiota of patients with CD recurrence exhibited a loose community structure, the microbiota of patients in remission displayed communities that were robustly correlated to each other. Microbiota colonising the neoterminal ileum and subanastomotic colon 6 months after ICR only differed in patients with recurrence. CONCLUSIONS: ICR modifies the gut microbiome. Remission after 6 months was associated with homogenous bacterial distribution around the anastomosis. Community structure and bacterial networks highlight target species, including Faecalibacterium prausnitzii and Ruminococcus gnavus, which may allow precise modulations of the overall microbial ecosystem towards remission pattern.