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Background: Irritable bowel syndrome (IBS) has been associated with changes in the intestinal microbiota. Only a few studies have explored differences in the mucosa-associated microbiota between IBS patients and healthy controls (HC)., Aims: To characterize and compare the microbiota in mucosal and fecal samples from carefully selected patients with IBS-D and HC., Methods: The cohort was composed of 23 diarrhea-predominant IBS (IBS-D) patients and 24 HC. Fresh stool samples were collected from participants prior to the collection of colonic mucosal samples from an unprepped bowel. After DNA extraction, 16S rRNA genes were sequenced by 454 pyrosequencing and analyzed using the QIIME pipeline., Results: The fecal microbiota (luminal niche) of IBS-D patients was found to have reduced enteric richness compared to HC (P < 0.05), whereas no differences were observed between the two groups within the mucosal microbiota. Within the luminal niche, the relative proportions of Faecalibacterium genus were found to be lower in IBS-D than in HC and the Dorea genus was higher in IBS-D. None of the taxa proportions were significantly different in IBS-D patients versus HC using an FDR of ≤ 0.1 when analyzing samples that appeared in > 25% samples of either niche., Conclusion: Fecal and mucosal microbiota of IBS-D patients and HC are very similar and are not sufficient to explain the reported altered physiology and symptomatology of IBS-D. Future studies should investigate intestinal microbiome-dependent functional activity in addition to the fecal and mucosal-associated microbial composition.

Irritable bowel syndrome (IBS) is one of the most common diagnoses made by healthcare providers. Yet the majority of patients with IBS are undiagnosed. The study by Sayuk et al. allows insight into the characteristics of different patient groups, e.g., with and without a formal diagnosis of diarrhea predominant IBS (IBS-D). We discuss the questions raised by this study regarding the importance of making a confident diagnosis, conveying it to patients and their implications for clinical practice.

Emerging data from epidemiologic, microbiome, and physiology research in patients with functional bowel disorders (FBDs) provide evidence for a linkage between alterations in the intestinal microbiota and FBDs. However, currently most of the data is based on association studies, and the causality role of the microbiota in these disorders is not established. Growing evidence for compositional changes and the increasing recognition of the association between the intestinal microbiota and gut-brain functions that are relevant to the pathophysiology and/or clinical symptoms of FBDs have led to increased interest in manipulating the intestinal microbiota for the treatment of these disorders., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Objectives: Bifidobacterium infantis 35624 is a probiotic that is used often in patients with irritable bowel syndrome (IBS). Non-patients with bowel symptoms may differ from patients with IBS in the impact of their bowel symptoms on illness severity, healthcare and treatment seeking behavior. The aim of this study is to assess the efficacy of B. infantis 35624 (10 9 c.f.u. per day) for the relief of abdominal discomfort and bloating in a non-patient population., Methods: A double-blind, randomized, placebo-controlled, parallel study with a 2-week placebo run-in phase followed by a 4-week intervention phase was conducted at ten clinical centers (USA). Subjects were recruited from the general population by advertisement. The study randomized 302 subjects who experienced abdominal discomfort and bloating ≥2-times per week for at least three months but have not seen a physician or received prescribed medication for their symptoms in the past 12 months. Subjects were assessed for pre- to post-intervention changes in symptom severity (on a 6-point Likert scale; 0=none, 5=very severe) and frequency (symptoms-free days)., Results: A total of 275 subjects (mean age 42 years, 79% female, 74% Caucasian) provided evaluable data. Overall mean severity scores at baseline were 2.4 for abdominal discomfort and 2.5 for bloating with no significant differences between the placebo and probiotic groups. Both groups showed significant (P<0.05) improvement in abdominal discomfort and bloating scores over the 4-week intervention period. Mean severity symptom scores at the end of intervention showed no significant differences between the probiotic and the placebo groups in either abdominal discomfort or bloating (P>0.3). The frequency of abdominal bloating-free days was greater in the B. infantis 35624 group compared to the placebo group (P<0.05). Both regimens were well tolerated., Conclusions: Unlike previous clinical studies in patients with IBS, B. infantis 35624 did not show a significant improvement in the mean severity of symptoms of abdominal discomfort and bloating in a non-patient population. This may be explained by the high placebo effect and the lower impact of functional bowel symptoms in the non-patient population.

Background: Recent studies demonstrated low-grade inflammation in patients with irritable bowel syndrome (IBS). However, these studies have been relatively small and do not enable examination of this factor in different subtypes of IBS and the possibility of confounding effects of comorbidities that may be associated with inflammatory responses., Goals: To investigate the association between high-sensitive C-reactive protein (hs-CRP) and the diagnosis of IBS, IBS subtypes, symptoms' severity, and IBS-associated comorbidities., Study: This cross-sectional study uses data from a large matched case-control study of IBS subjects and healthy controls (HC). hs-CRP levels were measured in all subjects. IBS diagnosis was determined by Rome III criteria, negative screening blood tests, and normal colonoscopy. Subjects were evaluated for IBS severity and associated pain and psychological comorbidities., Results: A total of 242 IBS patients and 244 HC were studied. Median hs-CRP levels in the IBS group were significantly higher than in HC (1.80; interquartile range, 0.7 to 4.04 mg/L vs. 1.20, interquartile range, 0.5 to 2.97 mg/L respectively, P<0.006). Levels were highest in IBS-D patients with greater disease severity. Hs-CRP levels mildly correlated with symptoms severity (r=0.169, P=0.009); this correlation was stronger for the IBS-D patients (r=0.27, P=0.006). IBS was a significant independent predictor (P=0.025) for higher hs-CRP levels, whereas other pain and psychological comorbidities were not., Conclusions: Given these observations of cross-sectional differences in hs-CRP between IBS subtypes and severity, independent of pain and comorbidities, more research is needed to explore a possible role of low-grade inflammation in the pathogenesis and/or clinical presentation of IBS.

Clostridium difficile is an anaerobic, gram positive, sporulating, toxin-producing bacillus which causes a spectrum of clinical disease ranging from an asymptomatic carrier state to toxic megacolon and fulminant disease. Infection with C. difficile is an expensive and pervasive health care burden. The current theory regarding the development of C. difficile infection (CDI) suggests that disruption of the structure and/or function of an individual's normal intestinal microbiota enables colonization by C. difficile, and in the absence of an effective immune response, the bacteria causes illness. In this article we discuss the role of the colonic microbiota in the development of CDI and the potential role of probiotics in preventing and treating CDI. We review the evidence from in vitro laboratory and pre-clinical studies, as well as evidence from clinical studies and discuss the current recommendations for the use of probiotics for CDI in clinical practice., (Copyright © 2016. Published by Elsevier Ltd.)

Functional bowel disorders (FBDs) are the most common gastrointestinal (GI) disorders seen by gastroenterologists and primary care physicians. The disorders affect patients functioning and quality of life (QOL) and are associated with significant healthcare burden. The current theory regarding the development of FBDs suggests brain-gut axis dysfunctions associated abnormal GI motility and sensation. Recent data suggest that alterations in the intestinal microbiota may have a role in the pathogenesis of FBDs; or at least have the potential to affect intestinal functions that are thought to be relevant to the development of functional GI symptoms. This has led to growing interest of healthcare providers and patients in targeting the intestinal microbiota for the treatment of FBDs. In this article we discuss the potential role probiotic interventions in the treatment of FBDs. We review the evidence from pre-clinical and clinical studies and discuss the current recommendations for the use of probiotics for FBDs in clinical practice., (Copyright © 2016. Published by Elsevier Ltd.)

Irritable bowel syndrome (IBS) is the most prevalent and the best studied functional gastrointestinal disorder. The etiology and the pathogenesis of IBS are still not clear; however, recent studies have implicated a role for alterations in the intestinal microbiota (dysbiosis) in the pathophysiology of the disorder. Epidemiological observations have demonstrated that the development of IBS symptoms is often preceded by a disruption of the individual's normal intestinal microbiota, and microbiological studies have demonstrated compositional differences in the intestinal microbiota between patients with IBS patients and healthy controls. In addition, animal studies and a few recent human clinical studies have demonstrated that compositional changes in the intestinal microbiota in IBS are associated with relevant abnormal gastrointestinal and brain-gut axis functions that are often observed in patients with IBS. This article discusses points of interest from the current research on the microbiota-gut-brain interactions in IBS and highlights the relevance of the emerging data to our understanding of the disorder and the clinical implications for patients' care.

This paper describes the consensus opinion of the participants in the 4th Triennial Yale/Harvard Workshop on Probiotic Recommendations. The recommendations update those of the first 3 meetings that were published in 2006, 2008, and 2011. Recommendations for the use of probiotics in necrotizing enterocolitis, childhood diarrhea, inflammatory bowel disease, irritable bowel syndrome and Clostridium difficile diarrhea are reviewed. In addition, we have added recommendations for liver disease for the first time. As in previous publications, the recommendations are given as A, B, or C ratings.

Background: The intestinal microbiota is associated with human health and diseases. The luminal microbiota (LM) and the mucosal-associated microbiota (MAM) are 2 distinct ecosystems with different metabolic and immunological functions., Aim: To characterize the intestinal LM and MAM in humans using high throughput sequencing of the 16S rRNA gene., Methods: Fresh fecal samples and distal colonic mucosal biopsies collected from 24 healthy subjects before (fecal) and during (mucosa) a flexible sigmoidoscopy of an un-prepared bowel. High throughput sequencing of the 16S rRNA gene was used to characterize bacterial communities. Sequences were processed using the QIIME pipeline., Results: LM and MAM populations were significantly different (ANOSIM: R = 0.49, P = 0.001). The LM displayed tighter clustering compared to the MAM (average weighted UniFrac distances 0.27 ± 0.05 vs. 0.43 ± 0.09, P < 0.001, respectively), and showed higher diversity (Shannon diversity index: 4.96 ± 0.37 vs 4.14 ± 0.56, respectively, P < 0.001). The dominant phyla in the LM and MAM were significantly different: Firmicutes (41.4% vs. 29.1%, FDR < 0.0001, respectively), Bacteroidetes (20.2% vs. 26.3%, FDR < 0.05, respectively), Actinobacteria (22% vs. 12.6%, FDR < 0.0001, respectively) and Proteobacteria (9.3% vs. 19.3%, FDR < 0.0001, respectively). The abundance of 56 genera differed significantly (FDR < 0.1) between the 2 niches. All of the genera in the fecal microbiota were present in the MAM while 10 genera were found to be unique to the MAM., Conclusion: The LM and MAM are distinct microbial ecosystems that differ significantly from each other in microbial diversity and composition. These two microbial niches should be investigated independently to better understand the role of the intestinal microbiota in health and disease.

The pathophysiology of irritable bowel syndrome (IBS) is believed to involve alterations in the brain-gut axis; however, the etiological triggers and mechanisms by which these changes lead to symptoms of IBS remain poorly understood. Although IBS is often considered a condition without an identified "organic" etiology, emerging evidence suggests that alterations in the gastrointestinal microbiota and altered immune function may play a role in the pathogenesis of the disorder. These recent data suggest a plausible model in which changes in the intestinal microbiota and activation of the enteric immune system may impinge upon the brain-gut axis, causing the alterations in gastrointestinal function and the clinical symptoms observed in patients with IBS. This review summarizes the current evidence for altered intestinal microbiota and immune function in IBS. It discusses the potential etiological role of these factors, suggests an updated conceptual model for the pathogenesis of the disorder, and identifies areas for future research.

The brain-gut axis allows bidirectional communication between the central nervous system (CNS) and the enteric nervous system (ENS), linking emotional and cognitive centers of the brain with peripheral intestinal functions. Recent experimental work suggests that the gut microbiota have an impact on the brain-gut axis. A group of experts convened by the International Scientific Association for Probiotics and Prebiotics (ISAPP) discussed the role of gut bacteria on brain functions and the implications for probiotic and prebiotic science. The experts reviewed and discussed current available data on the role of gut microbiota on epithelial cell function, gastrointestinal motility, visceral sensitivity, perception and behavior. Data, mostly gathered from animal studies, suggest interactions of gut microbiota not only with the enteric nervous system but also with the central nervous system via neural, neuroendocrine, neuroimmune and humoral links. Microbial colonization impacts mammalian brain development in early life and subsequent adult behavior. These findings provide novel insights for improved understanding of the potential role of gut microbial communities on psychological disorders, most particularly in the field of psychological comorbidities associated with functional bowel disorders like irritable bowel syndrome (IBS) and should present new opportunity for interventions with pro- and prebiotics.

Background: Recent studies have suggested a role for an altered intestinal microbiota in the pathophysiology of irritable bowel syndrome (IBS). However, no consensus has been reached regarding the association between specific enteric bacterial groups and IBS. The aim of this study was to investigate the fecal and mucosal-associated microbiota using two independent techniques in intestinal samples from diarrhea-predominant IBS (D-IBS) and healthy controls., Methods: Fecal and colonic mucosal biopsy samples were obtained from 10 D-IBS patients and 10 healthy controls. Colonic tissue was collected during a un-sedated un-prepped flexible sigmoidoscopy. Fecal and tissue samples were processed immediately upon collection for culture under aerobic and anaerobic conditions or frozen for further molecular analysis. DNA was extracted from all frozen samples and used to enumerate specific bacterial groups using quantitative real-time PCR (qPCR)., Results: Culture analysis of intestinal samples demonstrated a significant reduction in the concentration of aerobic bacteria in fecal samples from D-IBS patients when compared to healthy controls (1.4 × 107 vs. 8.4 × 108 CFUs/g feces, P = 0.002). qPCR analysis demonstrated a significant 3.6 fold increase (P = 0.02) in concentrations of fecal Lactobacillus species between D-IBS patients and healthy controls., Conclusions: Our culture and molecular data indicate that quantitative differences exist in specific bacterial groups in the microbiota between D-IBS and healthy subjects.

Background & Aims: Bloating symptoms are common in patients with irritable bowel syndrome (IBS) seen in primary care and gastrointestinal clinics. However, the underlying mechanisms of IBS are poorly understood, and there are few data available about the epidemiology of this syndrome or the impact of its symptoms. We investigated the prevalence, characteristics, and impact of bloating symptoms in patients with IBS., Methods: IBS patients were identified by Rome II criteria in a U.S. population representative web-based survey. Patients were asked about the quality, frequency, and severity of their gastrointestinal symptoms. The impact of these symptoms was investigated by assessing patients' health-related quality of life, utilization of health care, and use of medications., Results: Of the 337 IBS patients in this study, 82.5% (n = 278) reported bloating symptoms, the second most bothersome symptom after abdominal cramping. The symptoms were more prevalent in female patients, 87.4% (n = 209), than in male patients, 70.4% (n = 69) (P < .0001), and in patients with constipation, 88.7% (n = 47), and mixed symptoms, 88.8% (n = 135), than in patients with diarrhea, 72.3% (n = 96), (P = .02 and P < .01, respectively). Bloating symptoms were the third (of 14) most important reason to seek medical care, and more than half of the patients reported regular use of anti-gas medications. Bloating symptoms were associated with decreased energy levels (P = .04), food intake (P < .01), and physical functioning (P = .06)., Conclusions: Bloating symptoms are common in patients with IBS, and their prevalence and relative severity differ on the basis of sex and IBS subtype. Bloating symptoms are associated with a decrease in the quality of life and increases in health care utilization and use of medications.

Functional gastrointestinal disorders (FGIDs) are highly prevalent in Western countries yet no single mechanism or etiological agent that initiates IBS has been identified. Current research has implicated the intestinal microbiota with FGIDs. This article reviews the available literature/data regarding the intestinal microbiota and FGIDS. The possible relationships between the intestinal microbiota and the intestinal function and functional bowel symptoms are discussed.

Purpose: This study was designed to determine whether biofeedback is more effective than diazepam or placebo in a randomized, controlled trial for patients with pelvic floor dyssynergia-type constipation, and whether instrumented biofeedback is necessary for successful training., Methods: A total of 117 patients participated in a four-week run-in (education and medical management). The 84 who remained constipated were randomized to biofeedback (n=30), diazepam (n=30), or placebo (n=24). All patients were trained to do pelvic floor muscle exercises to correct pelvic floor dyssynergia during six biweekly one-hour sessions, but only biofeedback patients received electromyography feedback. All other patients received pills one to two hours before attempting defecation. Diary data on cathartic use, straining, incomplete bowel movements, Bristol stool scores, and compliance with homework were reviewed biweekly., Results: Before treatment, the groups did not differ on demographic (average age, 50 years; 85 percent females), physiologic or psychologic characteristics, severity of constipation, or expectation of benefit. Biofeedback was superior to diazepam by intention-to-treat analysis (70 vs. 23 percent reported adequate relief of constipation 3 months after treatment, chi-squared=13.1, P<0.001), and also superior to placebo (38 percent successful, chi-squared=5.7, P=0.017). Biofeedback patients had significantly more unassisted bowel movements at follow-up compared with placebo (P=0.005), with a trend favoring biofeedback over diazepam (P=0.067). Biofeedback patients reduced pelvic floor electromyography during straining significantly more than diazepam patients (P<0.001)., Conclusions: This investigation provides definitive support for the efficacy of biofeedback for pelvic floor dyssynergia and shows that instrumented biofeedback is essential to successful treatment.

Preclinical studies have shown that a very low dose of naltreoxone hydrochloride (NTX), an opiate antagonist, can block excitatory opioid receptors without affecting inhibitory opioid receptors, resulting in analgesic potency without side effects. The present study assessed the efficacy and safety of PTI-901 (low-dose NTX) treatment in Irritable bowel syndrome (IBS) patients. Forty-two IBS patients participated in an open-label study. Participants received 0.5 mg PTI-901/day for 4 weeks and were evaluated during baseline, during treatment, and at 4-week follow-up. Patients recorded degree of abdominal pain, stool urgency, consistency, and frequency. Primary outcomes were number of pain-free days and overall symptom relief, evaluated by a global assessment score. Data were analyzed per protocol. Global assessment improved in 76% of 42 patients. During treatment, the mean weekly number of pain-free days increased from 0.5+/-1 to 1.25+/-2.14 (P=0.011). There were no significant adverse reactions. PTI-901 improves pain and overall feeling, and is well tolerated by IBS patients. A large, randomized, double-blind, placebo-controlled study is justified.

Functional diarrhea (FD), one of the functional gastrointestinal disorders, is characterized by chronic or recurrent diarrhea not explained by structural or biochemical abnormalities. The treatment of FD is intimately associated with establishing the correct diagnosis. First, FD needs to be distinguished from diarrhea-predominant irritable bowel syndrome (IBS), in which, unlike in FD, abdominal pain is a primary diagnostic criterion. Next, FD must be differentiated from the myriad organic causes of chronic diarrhea. Unlike IBS, in which a positive diagnosis can be made with an acceptable level of confidence using symptom-based criteria and minimal testing, the diagnosis of FD is still primarily a diagnosis of exclusion. Thus, the onus is on the physician to eliminate potential underlying causes, both common and uncommon, in the proper clinical setting. Once the diagnosis has been established, the clinician and patient should first focus on identifying, eliminating, and/or treating aggravating factors. These may include physiologic factors (eg, small bowel bacterial overgrowth), psychological factors (eg, stress and anxiety), and dietary factors (eg, carbohydrate malabsorption). Thereafter, appropriate treatment for functional diarrhea may be instituted. Treatment options include dietary and lifestyle modification, pharmacologic therapies, and alternative modalities. Although many of these strategies have been studied in IBS, almost none of them has been examined specifically in FD. Furthermore, given the poorly understood pathophysiologic basis of FD, these treatments primarily target a patient's symptoms and presumed altered physiology rather than underlying etiologic mechanisms. Therefore, we stress that treatment must be approached in an individualized manner and that dietary and pharmacologic therapies should be part of a comprehensive therapeutic approach in which education and reassurance form the foundation. In general, we attempt to remove dietary triggers and recommend increased fiber intake. We then add anticholinergic, antispasmodic, antimotility, and antidiarrheal agents as the first line of pharmacotherapy. Should a patient not respond to these, and for patients who have a significant degree of psychological dysfunction, central acting agents, including antidepressants and/or anxiolytics, may be beneficial. During the treatment period, we also recommend that physicians keep an open mind. If signs or symptoms that suggest an ongoing or previously unrecognized organic process develop, then a re-evaluation of the clinical picture is indicated.

Background & Aims: Digestive and liver diseases are associated with substantial morbidity and mortality in the United States. Statistics about the incidence, prevalence, mortality, and resource utilization of digestive and liver diseases in the United States may be cumbersome to obtain because they are scattered in multiple sources. These data may be useful for policy makers, grant applicants, and authors., Methods: Data on the most common gastrointestinal and liver diseases were collected from large publicly available national databases. Information was collected on inpatient and outpatient gastrointestinal complaints and diagnoses, gastrointestinal cancers, and deaths from common liver diseases., Results: The leading gastrointestinal complaint prompting an outpatient visit is abdominal pain, with 12.2 million annual visits, followed by diarrhea, nausea, and vomiting. Abdominal pain is the leading outpatient gastrointestinal diagnosis, accounting for 5.2 million visits annually, followed by gastroesophageal reflux disease, with 4.5 million visits. Gallstone disease is the most common inpatient diagnosis, with 262,411 hospitalizations and a median inpatient charge of USD$11,584. Colorectal cancer is the most common gastrointestinal cause of death and is the most common gastrointestinal cancer, with an incidence of 54 per 100,000. Among gastrointestinal cancers, primary liver cancer had the highest increase in incidence from 1992 to 2000., Conclusions: Gastrointestinal and liver diseases are associated with significant outpatient and inpatient healthcare utilization. Following trends in utilization is important for determining allocation of resources for health care and research.

Previous studies have demonstrated alterations in brain response to rectal distension in patients with irritable bowel syndrome (IBS) compared to controls. Our aim was to compare regional brain activity in response to rectal balloon distension in patients with IBS and healthy controls. We studied six patients with IBS and six healthy controls. Positron emission tomography scans were obtained during rectal balloon distensions. Statistical parametric mapping and region of interest analysis were performed to identify and compare differences in regional cerebral blood flow (CBF) for each distension pressure within and between the groups of interest. In post-hoc analyses, patients with a history of sexual or physical abuse were compared to patients without abuse. In response to rectal distension, controls exhibit a greater increase in anterior cingulate cortex (ACC) activity compared to the IBS group (Z = 3.2, P = 0.001). Thalamic activity was higher in the IBS patients relative to the control group (Z = 3.3, P < 0.001). Increased ACC activity was observed in IBS patients with no history of abuse (Z = 5.2, P < 0.001) similar to controls, whereas no such increased activity was noticed in the abused group. In conclusion, this study replicates previous findings showing alterations in brain response to rectal distension in patients with IBS. The observations on the effect of abuse suggest a possible modulating role of abuse history on this brain response.

Background: Anxiety, discomfort, and high levels of concern can affect patient attitude toward endoscopic procedures as well as compliance and adherence to current recommendations for the examination. This study evaluated how patients perceive flexible sigmoidoscopy., Methods: A prospective study was conducted at two sites of 764 patients presenting for GI endoscopy (flexible sigmoidoscopy 175, colonoscopy 384, EGD 205). Before these procedures, patients rated their anticipated (preprocedure) difficulty and degree of concern for each of 30 specific concerns. After the procedure, the patients rated their actual (postprocedure) difficulty. Patients' levels of concerns and difficulty were compared before and after the procedure and among the 3 procedure types., Results: Before the procedure, patients who were to undergo flexible sigmoidoscopy had fewer concerns and lower scores for the severity of the concerns than did patients having colonoscopy or EGD. After the procedure, patients who had flexible sigmoidoscopy rated it as more difficult than patients who had colonoscopy or EGD. Patients who had colonoscopy and EGD graded their actual difficulty as less than their anticipated difficulty. However, patients who had flexible sigmoidoscopy rated the actual difficulty the same as the anticipated difficulty., Conclusions: Although patients have fewer concerns regarding flexible sigmoidoscopy than for the other endoscopic procedures, after the procedure they rate sigmoidoscopy as more difficult compared with postprocedure ratings by patients who underwent colonoscopy or EGD. This suggests that it may be necessary to change the perception of flexible sigmoidoscopy as being the best tolerated of the endoscopic procedures.