[Small intestinal bacterial overgrowth (SIBO) - Therapy, nutrition, microbiome]. / Bakterielle Fehlbesiedlung des Dünndarms (SIBO) ­ Therapie, Ernährung, Mikrobiom.

SIBO (small intestinal bacterial overgrowth) is defined by bacterial overgrowth or colonization of the small intestine in combination with gastrointestinal symptoms such as bloating, nausea, pain, diarrhoea, malabsorption and food intolerance. SIBO can be caused by various mechanisms such as reduced intestinal motility, altered gastrointestinal anatomy, reduced gastric acid or pancreatic enzyme production, altered bile acid metabolism, or immune defects. Accordingly, SIBO often develops secondary to different underlying diseases.Diet has a fundamental influence on the composition of the intestinal microbiome and is therefore also a potential pathomechanism in SIBO. Furthermore, food intolerances are common in SIBO patients. However, both aspects have so far been insufficiently investigated. Nevertheless, elemental diets, carbohydrate-reduced diets, as well as pre- and probiotics are potential therapy options.This article provides a summary of current knowledge on the pathophysiology, diagnosis and treatment of SIBO, with particular emphasis on the role of nutrition and the microbiome.

Dysbiosis and nutrition in steatotic liver disease: addressing the unrecognized small intestinal bacterial overgrowth (SIBO) challenge.

Steatotic liver disease (SLD) is characterized by hepatic fat accumulation, potentially causing major consequences such as liver decompensation. Currently, we lack medications for the treatment of SLD. Therapeutic recommendations for patients include a hypocaloric diet, weight loss, and physical activity. In particular, the Mediterranean diet is frequently recommended. However, this diet might exacerbate intestinal problems in a subset of patients with coexisting small intestinal bacterial overgrowth (SIBO). Previous studies have reported that SIBO is more predominant in patients with fatty liver than in healthy individuals. Both our research and the findings of others have highlighted a challenge related to nutritional therapy in patients with fatty liver who also suffer from SIBO inasmuch as SIBO induces several phenomena (like bloating or abdominal pain) that can adversely affect patients' quality of life and might be exacerbated by the Mediterranean diet. This may lower their adherence to the intervention. As a solution, we suggest introducing additional diagnostics (e.g., breath test) in patients with SLD who complain of SIBO-like symptoms. The next step is to modify their diets temporarily starting with several weeks of "elimination and sanitation." This would involve restricting products rich in fermentable sugars and polyols, while simultaneously treating the bacterial overgrowth. In summary, while the hypocaloric Mediterranean diet is beneficial for patients with fatty liver, those with coexisting SIBO may experience exacerbated symptoms. It is vital to consider additional diagnostics and dietary modifications for this subset of patients to address both liver and intestinal health concurrently.

Small Intestinal Bacterial Overgrowth-Pathophysiology and Its Implications for Definition and Management.

The concept of small intestinal bacterial overgrowth (SIBO) arose in the context of maldigestion and malabsorption among patients with obvious risk factors that permitted the small bowel to be colonized by potentially injurious colonic microbiota. Such colonization resulted in clinical signs, symptoms, and laboratory abnormalities that were explicable within a coherent pathophysiological framework. Coincident with advances in medical science, diagnostic testing evolved from small bowel culture to breath tests and on to next-generation, culture-independent microbial analytics. The advent and ready availability of breath tests generated a dramatic expansion in both the rate of diagnosis of SIBO and the range of associated gastrointestinal and nongastrointestinal clinical scenarios. However, issues with the specificity of these same breath tests have clouded their interpretation and aroused some skepticism regarding the role of SIBO in this expanded clinical repertoire. Furthermore, the pathophysiological plausibility that underpins SIBO as a cause of maldigestion/malabsorption is lacking in regard to its purported role in irritable bowel syndrome, for example. One hopes that the application of an ever-expanding armamentarium of modern molecular microbiology to the human small intestinal microbiome in both health and disease will ultimately resolve this impasse and provide an objective basis for the diagnosis of SIBO.

AGA Clinical Practice Update on Small Intestinal Bacterial Overgrowth: Expert Review.

DESCRIPTION: Thanks to ready access to hydrogen breath testing, small intestinal bacterial overgrowth (SIBO) is now commonly diagnosed among individuals presenting with a variety of gastrointestinal and even nongastrointestinal symptoms and is increasingly implicated in lay press and media in the causation of a diverse array of disorders. Its definition, however, remains controversial and true prevalence, accordingly, undefined. The purpose of this review, therefore, was to provide a historical background to the concept of SIBO, critically review current concepts of SIBO (including symptomatology, pathophysiology, clinical consequences, diagnosis and treatment), define unanswered questions and provide a road map toward their resolution. METHODS: Best Practice Advice statements were developed following discussion by the 3 authors. Two authors each developed text around certain Best Practice Advice based on a review of available literature. All 3 authors reviewed the complete draft and after discussion, redrafting, and further review and revision, all of the authors agreed on a final draft. BEST PRACTICE ADVICE 1: The definition of SIBO as a clinical entity lacks precision and consistency; it is a term generally applied to a clinical disorder where symptoms, clinical signs, and/or laboratory abnormalities are attributed to changes in the numbers of bacteria or in the composition of the bacterial population in the small intestine. BEST PRACTICE ADVICE 2: Symptoms traditionally linked to SIBO include bloating, diarrhea, and abdominal pain/discomfort. Steatorrhea may be seen in more severe cases. BEST PRACTICE ADVICE 3: There is insufficient evidence to support the use of inflammatory markers, such as fecal calprotectin to detect SIBO. BEST PRACTICE ADVICE 4: Laboratory findings can include elevated folate and, less commonly, vitamin B-12 deficiency, or other nutritional deficiencies. BEST PRACTICE ADVICE 5: A major impediment to our ability to accurately define SIBO is our limited understanding of normal small intestinal microbial populations-progress in sampling technology and techniques to enumerate bacterial populations and their metabolic products should provide much needed clarity. BEST PRACTICE ADVICE 6: Controversy remains concerning the role of SIBO in the pathogenesis of common functional symptoms, such as those regarded as components of irritable bowel syndrome. BEST PRACTICE ADVICE 7: Management should focus on the identification and correction (where possible) of underlying causes, correction of nutritional deficiencies, and the administration of antibiotics. This is especially important for patients with significant maldigestion and malabsorption. BEST PRACTICE ADVICE 8: Although irritable bowel syndrome has been shown to respond to therapy with a poorly absorbed antibiotic, the role of SIBO or its eradication in the genesis of this response warrants further confirmation in randomized controlled trials. BEST PRACTICE ADVICE 9: There is a limited database to guide the clinician in developing antibiotic strategies for SIBO, in any context. Therapy remains, for the most part, empiric but must be ever mindful of the potential risks of long-term broad-spectrum antibiotic therapy.

ACG Clinical Guideline: Small Intestinal Bacterial Overgrowth.

Small intestinal bacterial overgrowth is defined as the presence of excessive numbers of bacteria in the small bowel, causing gastrointestinal symptoms. This guideline statement evaluates criteria for diagnosis, defines the optimal methods for diagnostic testing, and summarizes treatment options for small intestinal bacterial overgrowth. This guideline provides an evidence-based evaluation of the literature through the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) process. In instances where the available evidence was not appropriate for a formal GRADE recommendation, key concepts were developed using expert consensus.

Small Intestinal Bacterial Overgrowth: Clinical Features and Therapeutic Management.

Small intestinal bacterial overgrowth (SIBO) is a common, yet underrecognized, problem. Its prevalence is unknown because SIBO requires diagnostic testing. Although abdominal bloating, gas, distension, and diarrhea are common symptoms, they do not predict positive diagnosis. Predisposing factors include proton-pump inhibitors, opioids, gastric bypass, colectomy, and dysmotility. Small bowel aspirate/culture with growth of 10-10 cfu/mL is generally accepted as the "best diagnostic method," but it is invasive. Glucose or lactulose breath testing is noninvasive but an indirect method that requires further standardization and validation for SIBO. Treatment, usually with antibiotics, aims to provide symptom relief through eradication of bacteria in the small intestine. Limited numbers of controlled studies have shown systemic antibiotics (norfloxacin and metronidazole) to be efficacious. However, 15 studies have shown rifaximin, a nonsystemic antibiotic, to be effective against SIBO and well tolerated. Through improved awareness and scientific rigor, the SIBO landscape is poised for transformation.

Management of Small Intestinal Bacterial Overgrowth in Adult Patients.

The human gastrointestinal tract is a complex system of digestive pathways aided by mechanical processes, enzymes, transport molecules, and colonic bacteria. Occasionally, these bacterial components transplant to atypical locations due to various gastrointestinal imbalances or anatomical structural issues. This may lead to bacterial overgrowth of the small intestine, where minimal or no bacteria are normally found. Symptoms of small intestinal bacterial overgrowth may mimic those of various functional gastrointestinal diseases. Small intestinal bacterial overgrowth is typically diagnosed through hydrogen breath tests or jejunal aspirate culture. Current recommendations indicate antibiotics as the first-line treatment to eradicate or modify the bacterial overgrowth to a more favorable state. Nutritional support is also indicated to correct deficiencies and aid in symptom alleviation. As small intestinal bacterial overgrowth is common in other conditions, much of the research for this area is based on findings in codisease states rather than independent disease research. To provide accurate recommendations for small intestinal bacterial overgrowth, more targeted research is needed.

The Spectrum of Small Intestinal Bacterial Overgrowth (SIBO).

PURPOSE OF REVIEW: To critically review recent (past 3 years) literature on the definition, diagnosis, and management of small intestinal bacterial overgrowth (SIBO). RECENT FINDINGS: While various series continue to illustrate the occurrence of SIBO in disease states where well-known risk factors for its occurrence are present (hypochlorhydria, disorders of intestinal structure or motor function, pancreatic insufficiency, and chronic liver disease, for example), the current challenge is in defining the limits of SIBO. Is SIBO truly common among those with "functional" gastrointestinal symptoms where there is no evidence of maldigestion or malabsorption; the original hallmarks of SIBO? Our attempts to address this question continue to be hampered by the limitations of our diagnostic tool kit. There is hope-the application of modern molecular techniques to the study of the small intestinal microbiome, together with some innovative sampling techniques, such as real-time intestinal gas sampling, may soon allow us to truly define the spectrum of SIBO. SIBO, once removed from its original confines as a cause of malabsorption syndrome, has proven to be an elusive and moving target. Only the most rigorous studies employing validated methodologies will finally corral this mysterious entity.

Testing and Treating Small Intestinal Bacterial Overgrowth Reduces Symptoms in Patients with Inflammatory Bowel Disease.

BACKGROUND: Common mechanisms against small intestinal bacterial overgrowth (SIBO), including an intact ileocecal valve, gastric acid secretion, intestinal motility, and an intact immune system, are compromised in inflammatory bowel disease (IBD), and therefore, a relatively high incidence of SIBO has been reported in this population. AIMS: We aimed to determine whether an improvement in IBD clinical activity scores is seen after testing and treating SIBO. METHODS: A retrospective cohort study of 147 patients with inflammatory bowel disease who were referred for SIBO breath testing from 1/2012 to 5/2016 was performed. Characteristics of SIBO positive and treated patients were compared to SIBO negative patients, including the changes in Partial Mayo Score or Harvey Bradshaw Index (HBI), using Student's t test for continuous variables and Chi-squared or Fisher's exact test for categorical variables. RESULTS: 61.9% were SIBO positive and treated, and 38.1% were SIBO negative. In Crohn's disease, the median HBI decreased from 5 to 3 and 5 to 4, in the SIBO positive and negative groups, respectively (p = 0.005). In ulcerative colitis, the Partial Mayo Score decreased from 2 to 1.5 and 2 to 1, respectively (p = 0.607). CONCLUSIONS: This study examines the clinical effect of testing and treating for SIBO in an IBD population. We see a significant reduction in HBI after testing for and treating SIBO. Future prospective studies are necessary to further investigate the role of SIBO in the evaluation and management of IBD.

Small Intestinal Bacterial Overgrowth: Nutritional Implications, Diagnosis, and Management.

Small intestinal bacterial overgrowth (SIBO), characterized by the presence of excessive bacteria in the small intestine, is typically described as a malabsorptive syndrome occurring in the context of gut stasis syndromes. SIBO is now considered to be a disorder associated with diverse clinical conditions without classic risk factors for SIBO and a cause of several nonspecific gastrointestinal and nongastrointestinal symptoms. Because there is currently no gold standard for diagnosing SIBO, its prevalence and role in the pathogenesis of other diseases remain uncertain; as does optimal treatment of patients with relapsing symptoms.

Integrative Treatment of Chronic Abdominal Bloating and Pain Associated With Overgrowth of Small Intestinal Bacteria: A Case Report.

Context • Small intestinal bacterial overgrowth (SIBO) is commonly defined as an increased number of bacteria and/or an abnormal type of bacteria in the small intestine. Conventional treatment for SIBO is typically focused on antibiotics to eradicate the bacterial overgrowth. Numerous studies have demonstrated the antimicrobial activity of herbs, and a diet low in fermentable oligo-, di-, and monosaccharides and polyols (FODMAPs) has been shown to enhance antibiotic therapy. Objective • The current case study intended to evaluate the benefits of an alternative, multifaceted approach-including botanical and homeopathic therapies in conjunction with a low-FODMAP diet-in the treatment of SIBO and its associated symptoms. Design • The research team performed a case study. Setting • The study was conducted at SCNM Medical Center (Tempe, AZ, USA). Participant • The participant was a female patient at the SCNM Medical Center with chronic, daily, severe abdominal bloating and pain that particularly worsened after meals and by the end of the day. The patient also had a significant history of chronic constipation that had begun approximately 10 y prior to her experiencing the daily abdominal pain. Intervention • Based on a lactulose breath test for hydrogen and methane, the research team diagnosed the patient with a case of mild SIBO. The treatment approach was multifaceted, involving a low-FODMAP diet, antimicrobial botanical therapy, and homeopathic medicine. Results • The patient's abdominal pain and bloating resolved with the treatment of the SIBO, although her underlying constipation, which was likely associated with other factors, remained. Conclusions • This case study supports an alternative, multifaceted approach to the treatment of SIBO and commonly associated symptoms.

Small Intestinal Bacterial Overgrowth and Irritable Bowel Syndrome: A Bridge between Functional Organic Dichotomy.

The pathogenesis of irritable bowel syndrome (IBS), once thought to be largely psychogenic in origin, is now understood to be multifactorial. One of the reasons for this paradigm shift is the realization that gut dysbiosis, including small intestinal bacterial overgrowth (SIBO), causes IBS symptoms. Between 4% and 78% of patients with IBS and 1% and 40% of controls have SIBO; such wide variations in prevalence might result from population differences, IBS diagnostic criteria, and, most importantly, methods to diagnose SIBO. Although quantitative jejunal aspirate culture is considered the gold standard for the diagnosis of SIBO, noninvasive hydrogen breath tests have been popular. Although the glucose hydrogen breath test is highly specific, its sensitivity is low; in contrast, the early-peak criteria in the lactulose hydrogen breath test are highly nonspecific. Female gender, older age, diarrhea-predominant IBS, bloating and flatulence, proton pump inhibitor and narcotic intake, and low hemoglobin are associated with SIBO among IBS patients. Several therapeutic trials targeting gut microbes using antibiotics and probiotics have further demonstrated that not all symptoms in patients with IBS originate in the brain but rather in the gut, providing support for the micro-organic basis of IBS. A recent proof-of-concept study showing the high frequency of symptom improvement in patients with IBS with SIBO further supports this hypothesis.

How to Test and Treat Small Intestinal Bacterial Overgrowth: an Evidence-Based Approach.

Small intestinal bacterial overgrowth (SIBO) is characterized by an excessive amount of bacteria in the small intestine and a constellation of symptoms that include bloating, pain, gas, and diarrhea. Although known for many decades, there is a lack of consensus and clarity regarding the natural history and methods for its diagnosis. Several tests have been proposed, including the glucose breath test, lactulose breath test, small intestinal aspiration and culture, and others. However, there is a lack of standardization of these tests and their interpretation. Treatment of SIBO remains empirical; generally, broad spectrum antibiotics are recommended for 2 weeks (amoxicillin, rifaximin, ciprofloxacin, etc.) but evidence for their use is fair. Clearly, there is a strong need to develop a systematic approach for the management of SIBO and to perform multicenter clinical trials for the treatment of SIBO. In this review, we will discuss the current evidence for the diagnosis and treatment of SIBO, which includes (1) elimination/modification of the underlying causes, (2) induction of remission (antibiotics and elemental diet), and (3) maintenance of remission (promotility drugs, dietary modifications, repeat or cyclical antibiotics).

Small intestinal bacterial overgrowth: what it is and what it is not.

PURPOSE OF REVIEW: To critically review recent literature on small intestinal bacterial overgrowth (SIBO). RECENT FINDINGS: When originally described, SIBO was added to the list of causes of the malabsorption syndrome and the pathophysiology of its consequences for the digestion and absorption of various nutrients was gradually revealed. More recently, SIBO was incriminated as a cause of diarrhea, especially in the elderly. However, the suggestion that SIBO may be a causative factor in irritable bowel syndrome and of its constituent symptoms has sparked debate and controversy on the very definition of SIBO. This debate revolves around the tests employed and the diagnostic cut-off values (for bacterial numbers) used to diagnose SIBO in clinical practice. SUMMARY: A fundamental problem with SIBO, and one that allows controversy to simmer, is the lack of a universally accepted and applied gold standard for the diagnosis of SIBO. Hopefully, the application of molecular microbiological methods to the characterization of the small intestinal microbiome will tell us, once and for all, what is normal and when 'abnormality' is truly responsible for symptoms and disease. Meanwhile, therapy remains, for the most part, empirical and is based on the correction, wherever possible, of any underlying cause, attention to nutritional deficiencies, and the use of antibiotics.

Effect of probiotic or prebiotic supplementation on antibiotic therapy in the small intestinal bacterial overgrowth: a comparative evaluation.

UNLABELLED: Bacterial intestinal overgrowth syndrome (SIBO) treatment is based on antibiotics. Probiotics have been shown to give similar results, whilst no study is available about prebiotics. This study evaluated the addition of probiotics or prebiotics to antibiotics on SIBO symptoms in a 6-month follow-up. We enrolled 40 patients (14 males and 26 females) reporting abdominal compliant without gastrointestinal diseases/alarm symptoms. SIBO was diagnosed by the agreement of lactulose and glucose breath tests. Patients were randomly divided into two groups homogeneous for sex and age: group 1 received Rifaximin 400 mg/day for 7 days/month followed by Lactobacillus casei for 7 days more and group 2 antibiotic followed by short chain fructo-oligosaccharides. All patients recorded a questionnaire for subjective symptom evaluation according to Rome III criteria and Bristol scale for stool characters before the study and after 6 months. STATISTICS: Student's t and Fisher's exact tests. In group 1, a significant improvement was obtained in 5 out of 6 symptoms, whilst in group 2 in 4 out of 6 symptoms (nausea and number of bowel movements failed to improve). Despite we observed a trend of probiotics to be more effective than prebiotics, the difference in the percentage of improved symptoms was not significant (83,3% vs 66.6%; p= 0.57). Our preliminary data show a good outcome with sequential antibioticprobiotic/ prebiotic administration in patients with SIBO.

Short- and long-term effects of a lactose-restricted diet and probiotics in children with chronic abdominal pain: a retrospective study.

OBJECTIVE: To determine the short- and long-term effect of treatment in children with chronic abdominal pain (CAP). METHODS: A database with the results of H(2) breath test of children with CAP was created. All children with an abnormal test result were included and classified as small intestinal bacterial overgrowth (SIBO) or lactose intolerant (LTI). SIBO was treated with probiotics and LTI with a lactose-restricted diet. CAP was evaluated 5 months and 15 months after the test. RESULTS: 37 children (41%) were included. 17 LTI children (94%) improved after 5 months and 11 children (61%) after 15 months (P<0.05). Seven SIBO children improved after 5 months and 4 children after 15 months. In the combination group all 4 children improved after 5 months and 3 children after 15 months. CONCLUSION: Children with CAP caused by LTI or SIBO had less CAP after 5 months. This positive effect persists only in half of the children.

Medical update and potential advances in the treatment of pediatric intestinal failure.

Short bowel syndrome (SBS) and intestinal failure are chronic malabsorption disorders with considerable nutritional and growth consequences in children. Intestinal failure occurs when the functional gastrointestinal mass is reduced even if there is normal anatomical gastrointestinal length. A number of management strategies are often utilized to achieve successful intestinal rehabilitation and maintain adequate nutrition to avoid intestinal transplant. These strategies include minimizing the effect of parenteral associated liver disease, limiting catheter complications, and treating bacterial overgrowth in the remaining small intestine. In addition, there continues to be significant research interest in enhancing intestinal adaptation with targeted therapies. The purpose of this review is to discuss current perspectives and to highlight recent medical advances in novel investigational therapies.

Diarrhoea due to small bowel diseases.

Small intestinal diseases are a common, though often overlooked cause of diarrhoeal illness. Fully 1% of the Caucasian population are affected by coeliac disease and a substantial portion of children living in poverty in the developing world are affected by environmental enteropathy. These are but two examples of the many diseases that cause mucosal injury to the primary digestive and absorptive organ in our body. While diarrhoea may be a common, though not universally seen symptom of small bowel mucosal disease, the consequent malabsorption can lead to substantial malnutrition and nutrient deficiencies. The small intestine, unlike the colon, has been relatively inaccessible, and systematic evaluation is often necessary to identify and treat small intestinal mucosal diseases that lead to diarrhoea. Immunodeficiency states, including HIV enteropathy, adult autoimmune enteropathy, drug-associated enteropathy, and tropical sprue continue to occur and require specific therapy. All patients with severe diarrhoea or diarrhoea associated with features suggestive of malabsorption may have a disease of the small intestinal mucosa that requires careful evaluation and targeted management.