Bacterial flora as a cause or treatment of chronic diarrhea

Intestinal microflora can be considered an organ of the body. It has several functions in the human gut, mostly metabolic and immunologic, and constantly interacts with the intestinal mucosa in a delicate equilibrium. Chronic diarrhea is associated with an alteration of gut microbiota when a pathogen invades the gut and also in several conditions associated with intestinal mucosal damage or bowel dysfunction, as in inflammatory bowel disease, irritable bowel syndrome, or small bowel bacterial overgrowth. This article discusses the basis of gut microbiota modulation. Evidence for the efficacy of gut microbiota modulation in chronic conditions is also discussed.     

粪菌移植的研究现状、存在问题与发展方向

粪菌移植已经用于治疗难治性难辨梭状芽孢杆菌感染、炎症性肠病、腹泻型和便秘型肠易激综合征。但哪些患者适合用,哪些人适合做供体,怎么样是理想的移植方法等问题还没有完全解决,有关其机制、技术标准化、安全性评估等方面尚处于起步阶段,有待于深入研究。本文对FMT的研究现状、存在问题与发展方向作一介绍,并提出粪人工组合菌群移植是未来重要研究方向。     

Methodological issues in the study of intestinal microbiota in irritable bowel syndrome

Irritable bowel syndrome (IBS) is an intestinal functional disorder with the highest prevalence in the industrialized world. The intestinal microbiota (IM) plays a role in the pathogenesis of IBS and is not merely a consequence of this disorder. Previous research efforts have not revealed unequivocal microbiological signatures of IBS, and the experimental results are contradictory. The experimental methodologies adopted to investigate the complex intestinal ecosystem drastically impact the quality and significance of the results. Therefore, to consider the methodological aspects of the research on IM in IBS, we reviewed 29 relevant original research articles identified through a PubMed search using three combinations of keywords: “irritable bowel syndrome + microflora”, “irritable bowel syndrome + microbiota” and “irritable bowel syndrome + microbiome”. For each study, we reviewed the quality and significance of the scientific evidence obtained with respect to the experimental method adopted. The data obtained from each study were compared with all considered publications to identify potential inconsistencies and explain contradictory results. The analytical revision of the studies referenced in the present review has contributed to the identification of microbial groups whose relative abundance significantly alters IBS, suggesting that these microbial groups could be IM signatures for this syndrome. The identification of microbial biomarkers in the IM can be advantageous for the development of new diagnostic tools and novel therapeutic strategies for the treatment of different subtypes of IBS.     

Microbial signatures in post-infectious irritable bowel syndrome – toward patient stratification for improved diagnostics and treatment

Irritable bowel syndrome (IBS) is a multifactorial and heterogeneous disorder estimated to affect over 10% of the Western population. A subset of the patients reports the start of the disease after an episode of gastroenteritis. The alterations in the intestinal microbiota of the post-infectious IBS (PI-IBS) patients were recently investigated in a British cohort and shown to differentiate from the healthy controls and resemble that of diarrhea-predominant IBS (IBS-D) patients. The altered 27 genus-like groups created a microbial signature, which could be used to objectively stratify patients and healthy controls. In this addendum, we combine the microbiota data derived from the British cohort with that of a recently reported Swedish PI-IBS cohort. Remarkably, robust and reproducible microbiota signatures were observed in these PI-IBS patients. We discuss these results with attention on the emerging role of microbiota in the classification, development and treatment of PI-IBS.Key words: irritable bowel syndrome, IMD, microbiota, PI-IBS     

Gastrointestinal symptoms in the irritable bowel compared with peptic ulcer and inflammatory bowel disease.

Symptoms of 50 patients with the irritable bowel syndrome were compared with those of 49 with endoscopically proven peptic ulcer disease and 49 with radiologically or endoscopically proven inflammatory bowel disease using a questionnaire which was administered after the diagnosis was made. Symptoms of bowel dysfunction including pain related to bowel movements were more likely to occur in the irritable bowel syndrome than peptic ulcer disease. Only abdominal distension, straining at stool and scybala, however, were significantly more likely in the irritable bowel syndrome than inflammatory bowel disease. Four symptoms previously shown to be more common in irritable bowel syndrome than in organic abdominal disease were combined. The more of these symptoms that were present, the more likely were the patients to have the irritable bowel syndrome than peptic ulcer disease. Symptoms of gut dysfunction are highly discriminating between irritable bowel syndrome and peptic ulcer disease but less so between irritable bowel syndrome and inflammatory bowel disease.     

Role of gut microbiota via the gut-liver-brain axis in digestive diseases

The gut-brain axis is a bidirectional information interaction system between the central nervous system(CNS) and the gastrointestinal tract, in which gut microbiota plays a key role. The gut microbiota forms a complex network with the enteric nervous system, the autonomic nervous system, and the neuroendocrine and neuroimmunity of the CNS, which is called the microbiota-gut-brain axis. Due to the close anatomical and functional interaction of the gut-liver axis, the microbiota-gut-liver-brain axis has attracted increased attention in recent years. The microbiota-gut-liver-brain axis mediates the occurrence and development of many diseases, and it offers a direction for the research of disease treatment. In this review, we mainly discuss the role of the gut microbiota in the irritable bowel syndrome, inflammatory bowel disease, functional dyspepsia, non-alcoholic fatty liver disease, alcoholic liver disease, cirrhosis and hepatic encephalopathy via the gut-liver-brain axis, and the focus is to clarify the potential mechanisms and treatment of digestive diseases based on the further understanding of the microbiota-gut-liver-brain axis.     

A Molecular Analysis of Fecal and Mucosal Bacterial Communities in Irritable Bowel Syndrome

Purpose  

The objectives of this study were, firstly, to determine the diversity of the host’s gut microbiota in irritable bowel syndrome (IBS) using a culture-independent method (DGGE of the 16S rRNA gene) and, secondly, to examine mucosal biopsies of IBS patients and compare them to their own fecal microbiota.     

Prevalence of irritable bowel syndrome among undergraduates in Southeast China

BACKGROUND: There is a wide range in reported prevalence of irritable bowel syndrome worldwide. From the data appeared recently in medical literatures in China, it seems that the incidence of irritable bowel syndrome in young adults is not dissimilar to the one in the Western countries. AIMS: To explore the prevalence and epidemiological variations of irritable bowel syndrome in an undergraduate student population in Southeast China on the basis of the Rome II and Rome III criteria. METHODS: All the undergraduate student participants were administered self-report diagnostic measures for irritable bowel syndrome. RESULTS: The sex-adjusted prevalence rate of irritable bowel syndrome was 4.7% (Rome II) and 10.4% (Rome III), respectively. When we combined irritable bowel syndrome mixed and irritable bowel syndrome unsubtyped in the Rome III subgroups into one group considering the counterpart in the Rome II subgroups was alternative irritable bowel syndrome, the agreement between the two ways to subdivide these 54 patients who were identified with irritable bowel syndrome by both the two criteria was 81%, with a kappa value of 0.67. By the Rome III criteria, we found a female predominance which was especially attributed to the subtypes of irritable bowel syndrome with constipation and unsubtyped. CONCLUSIONS: Our study suggests that, in young adults in Southeast China, changing diagnostic criteria for irritable bowel syndrome from Rome II to Rome III may affect women more than men on not only the overall prevalence rate but also the sex-difference present or not, especially in irritable bowel syndrome with constipation and irritable bowel syndrome unsubtyped subgroups.     

RETRACTED ARTICLE: Gut microbiota and related diseases: clinical features

Intestinal microbiota is essential for gut homeostasis. Specifically, the microorganisms inhabiting the gut lumen interact with the intestinal immune system, supply key nutrients for the major components of the gut wall, and modulate energy metabolism. Host–microbiome interactions can be either beneficial or deleterious, driving gastrointestinal lymphoid tissue activities and shaping gut wall structures. This overview briefly focuses on the potential role played by abnormalities in gut microbiota and relative responses of the gastrointestinal tract in the determination of important pathological conditions such as the irritable bowel syndrome, inflammatory bowel diseases and colorectal cancer.     

Relation among personality and symptoms in nonulcer dyspepsia and the irritable bowel syndrome

The importance of personality traits in nonulcer dyspepsia and irritable bowel syndrome is a controversial issue. We wished to assess the distribution of abnormal personality traits in nonulcer dyspepsia and the irritable bowel syndrome, define any relation among personality and symptoms, and determine whether personality factors discriminate among patients with functional, psychiatric, or organic gastrointestinal diseases. Patients with nonulcer dyspepsia (n = 31), irritable bowel syndrome (n = 67), organic gastrointestinal disease (n = 64), somatoform disorder (n = 36) and healthy controls (n = 128) were studied. Before diagnostic evaluation by an independent physician, all patients completed the Minnesota Multiphasic Personality Inventory and a symptom questionnaire. Symptom scores for abdominal pain and the Manning criteria, which is considered to be diagnostic for the irritable bowel syndrome, were evaluated. Personality scales in patients with nonulcer dyspepsia, irritable bowel syndrome, and organic disease were very similar. However, patients in the other groups differed from somatoform disorder on nearly all scales. In nonulcer dyspepsia, irritable bowel syndrome, and organic disease, hypochondriasis weakly correlated with pain. Subgroups of irritable bowel syndrome patients with predominant constipation and those with predominant diarrhea had similar personality traits, although hypomania was minimally increased in constipation. Patients who fulfilled the Manning criteria for irritable bowel syndrome had more psychological distress than those who did not. The Minnesota Multiphasic Personality Inventory correctly classified somatoform disorder and health 81% and 75% of the time, respectively, but it classified nonulcer dyspepsia and irritable bowel syndrome correctly in only 32% and 34% of cases. Our results suggest that psychopathology may not be the major explanation for functional gastrointestinal disorders.     

Diagnostic value of the Manning criteria in irritable bowel syndrome.

Because unexplained 'functional symptoms' are a major cause of referral to gastroenterologists, the efficiency of the medical history to lead to a positive diagnosis of irritable bowel syndrome, without resorting to the use of expensive tests, remains a key question. Whilst the six criteria of Manning et al are widely used, data on their validity in discriminating irritable bowel syndrome from healthy controls, irritable bowel syndrome from non-ulcer dyspepsia and especially among irritable bowel syndrome subgroups, are not available. To evaluate this, we studied 361 outpatients who completed a bowel disease questionnaire, which objectively measured Manning's (and other) criteria. The group included 82 patients with irritable bowel syndrome, 33 with non-ulcer dyspepsia, 101 with organic gastrointestinal disease, and 145 healthy controls. Diagnoses were based on a full and independent clinical evaluation, not on responses to the bowel disease questionnaire. Reliability was assessed by a test-retest procedure. All six of the individual Manning criteria were found to be reliable (median kappa = 0.79). Based on a logistic regression analysis of the discriminatory value of Manning's criteria, as the number of positive criteria increased, so did the predicted probability of irritable bowel syndrome. This predictive value was highest in younger patients and in females. The Manning criteria discriminated irritable bowel syndrome from organic gastrointestinal disease and from all non-irritable bowel syndrome gastrointestinal disease with a sensitivity of 58% and 42%, and a specificity of 74% and 85%, respectively. Stools that were often loose and watery provided an additional independent criterion for distinguishing irritable bowel syndrome from non-irritable bowel syndrome. Thus, symptoms can be used to diagnose irritable bowel syndrome positively, but Manning's criteria are not highly sensitive.     

More accurate diagnosis of irritable bowel syndrome by the use of ''non-colonic'' symptomatology.

The criteria now used in an attempt to distinguish irritable bowel syndrome from organic gastrointestinal disease rely almost entirely on symptoms of colonic origin. 'Non-colonic' symptoms, however, arising either from elsewhere in the gut or of a more general nature, are common in irritable bowel syndrome and may have even better diagnostic potential. The prevalence of these non-colonic features was assessed in 107 patients with the irritable bowel syndrome and 295 subjects with other gut disorders. Gastrointestinal type non-colonic symptoms are useful in differentiating irritable bowel syndrome from inflammatory bowel disease but, with the exception of early satiety, are not helpful when there is gastro-oesophageal or biliary disease. More general 'non-colonic' features, such as lethargy and backache, are much commoner in irritable bowel syndrome than in all the organic gastrointestinal diseases studied and have good discriminant function. Multiple logistic regression analysis identified certain features that had a particularly significant independent risk for irritable bowel syndrome. Those were lethargy (relative risk 6.7), incomplete evacuation (RR 5.2), age under 40 (RR 2.1), backache (RR 2.0), early satiety (RR 1.8), and frequency of micturition (RR 1.8). These relative risks can be multiplied together to give an overall risk when more than one of these features is present in a patient. Until a diagnostic test is available more confident diagnosis of irritable bowel syndrome can be achieved by identifying symptoms that have good discriminant function. The results of this study indicate that the non-colonic features of irritable bowel syndrome may be especially valuable in this respect.     

Irritable bowel syndrome in the gynecological clinic

A study of the prevalence of symptoms suggestive of irritable bowel syndrome in 798 women referred to a gynecological clinic is reported; 321 women referred to dermatology and ear, nose, and throat clinics served as controls. Data were collected by a mailed symptom questionnaire. The prevalence of irritable bowel syndrome in the gynecological group was 37.3% compared with 27.7% in controls (P=0.003). Approximately 50% of women referred with abdominal pain, dyspareunia, and dysmenorrhea had symptoms compatible with irritable bowel syndrome (P<0.005), whereas the prevalence in those referred for cervical abnormalities, termination/sterilization or perineal problems was similar to that of controls (28%). Patients referred with urinary symptoms, heavy periods, nonmenstrual bleeding, vaginal discharge, and infertility had an intermediate prevalence of irritable bowel syndrome (35–45%). This study suggests that either many women with irritable bowel syndrome are being wrongly referred to gynecologists or raises the possibility that symptoms currently regarded as indicative of irritable bowel syndrome may be associated with certain gynecological disorders.     

Therapies aimed at the gut microbiota and inflammation: antibiotics, prebiotics, probiotics, synbiotics, anti-inflammatory therapies

Several recent observations have raised the possibility that disturbances in the gut microbiota and/or a low-grade inflammatory state may contribute to symptomatology and the etiology of irritable bowel syndrome (IBS). Consequent on these hypotheses, several therapeutic categories have found their way into the armamentarium of those who care for IBS sufferers. These agents include probiotics, prebiotics, antibiotics, and anti-inflammatory agents.     

The public awareness of the prevalence and impact of irritable bowel syndrome in the United States: perception versus reality

OBJECTIVES: The objectives of this survey were to assess the public perception of irritable bowel syndrome with respect to its prevalence and impact on society and to assess the public's knowledge of this condition. METHODS: A telephone survey of 1014 adults (487 women and 527 men), aged 18 or older, was conducted in the United States in May of 2002. Telephone numbers were selected by a random digit-dialing technique to ensure an independent sample. The interview comprised a standard set of demographic questions and 3 questions related to 5 chronic medical conditions: irritable bowel syndrome, asthma, coronary heart disease, depression, and diabetes. Responses to survey questions were tabulated according to demographic factors. RESULTS: Only 1.2% of the respondents thought that irritable bowel syndrome affected more Americans than did the other 4 chronic conditions, and only 8.6% believed irritable bowel syndrome to be the second leading cause of absenteeism from work or school. Nearly half (44.2%) of the respondents stated that, of the 5 disorders, they knew the least about irritable bowel syndrome. CONCLUSIONS: The survey results demonstrate a striking gap between the public perception of irritable bowel syndrome and reality, as well as a lack of public knowledge about irritable bowel syndrome. These findings reinforce the need for public education initiatives to raise awareness and knowledge about the prevalence and impact of irritable bowel syndrome.     

Microbial community analysis reveals high level phylogenetic alterations in the overall gastrointestinal microbiota of diarrhoea-predominant irritable bowel syndrome sufferers

Background  

A growing amount of scientific evidence suggests that microbes are involved in the aetiology of irritable bowel syndrome (IBS), and the gastrointestinal (GI) microbiota of individuals suffering from diarrhoea-predominant IBS (IBS-D) is distinguishable from other IBS-subtypes. In our study, the GI microbiota of IBS-D patients was evaluated and compared with healthy controls (HC) by using a high-resolution sequencing method. The method allowed microbial community analysis on all levels of microbial genomic guanine plus cytosine (G+C) content, including high G+C bacteria.     

Fatigue in irritable bowel syndrome: characterization and putative role of leptin

OBJECTIVES: Fatigue has received little attention in the irritable bowel syndrome. Emerging evidence exists that leptin may be involved in the pathogenesis of fatigue in several conditions. We aimed to evaluate the occurrence of fatigue and its characteristics in irritable bowel syndrome and to analyze the relationship between fatigue and leptin. METHODS: We enrolled 51 consecutive irritable bowel syndrome patients and 22 healthy controls without fatigue. None of them were depressed. The Fatigue Impact Scale was used to evaluate fatigue. RESULTS: In all, 62.7% of irritable bowel syndrome patients verbally expressed fatigue and rated more than 4 on the visual analog scale. The total score of fatigue was significantly higher in irritable bowel syndrome than in controls. In irritable bowel syndrome patients, but not in controls, a significant association was found between the total score of fatigue and leptin and this association was more pronounced in 32 irritable bowel syndrome patients who verbally expressed fatigue (r=0.60; P=0.0003). In irritable bowel syndrome, leptin correlated with fatigue independently from age, sex, fat mass and body mass index. CONCLUSIONS: Our study shows that fatigue occurs in 62.7% of irritable bowel syndrome patients when systematically asked for. Fatigue influences all three domains of the Fatigue Impact Scale in irritable bowel syndrome, the most being the physical and the psychosocial domains. Fatigue is associated with circulating leptin levels independently from age, sex, fat mass and body mass index in irritable bowel syndrome. The metabolic sequence involved in the occurrence of fatigue remains to be determined.     

New insights into the pathogenesis and pathophysiology of irritable bowel syndrome.

The pathogenesis and pathophysiology of irritable bowel syndrome is complex and still incompletely known. Potential pathogenetic factors include genes, infectious events, psychological symptoms and other loosely defined environmental factors. Both alterations at the central and peripheral level are thought to contribute to the symptoms of irritable bowel syndrome, including psychosocial factors, abnormal gastrointestinal motility and secretion, and visceral hypersensitivity. Today irritable bowel syndrome is viewed upon as a disorder of dysregulation of the so-called brain-gut axis, involving abnormal function in the enteric, autonomic and/or central nervous systems, with peripheral abnormalities probably dominating in some patients and disturbed central processing of signals from the periphery in others. Lines of evidence also suggest that inflammation within the gastrointestinal tract may be of great importance in at least subgroups of irritable bowel syndrome patients. To conclude, a complex picture of the pathogenesis and pathophysiology of irritable bowel syndrome is emerging, with interactions between several different alterations resulting in the divergent symptom pattern in these patients.     

青少年肠易激综合征调查表的制定及考评

目的制定青少年肠易激综合征调查表。方法采用选题小组和议题小组的程序化决策方式来制定青少年肠易激综合征调查表．并通过对247例中学生的测试对调查表进行信度、效度及反应度考评。结果制定出含45个条目的青少年肠易激综合征调查表。饮食习惯、诊断标准、诱发因素、胃肠道症状及躯体精神5个领域的克郎巴赫系数分别为0．668、0．752、0．824、0．749及0．824。主成分累积贡献率为70．72％。结论青少年肠易激综合征调查表具有较好的信度、效度及反应度，可作为青少年肠易激综合征流行病学调查的测评工具。