High dosage rifaximin for the treatment of small intestinal bacterial overgrowth

Review article: A practical approach to persistent gastrointestinal symptoms in inflammatory bowel disease in remission

BACKGROUND

Persistent gastrointestinal symptoms are prevalent in adult patients with inflammatory bowel disease (IBD), even when endoscopic remission is reached. These symptoms can have profound negative effects on the quality of life of affected patients and can be difficult to treat. They may be caused by IBD-related complications or comorbid disorders, but they can also be explained by irritable bowel syndrome (IBS)-like symptoms.

AIMS

To provide a practical step-by-step guide to diagnose and treat persistent gastrointestinal symptoms in patients with IBD in remission via a personalised approach.

METHODS

We scrutinised relevant literature on causes, diagnostics and treatment of persistent gastrointestinal symptoms (abdominal pain or discomfort, bloating, abdominal distension, diarrhoea, constipation and faecal incontinence) in patients with IBD in remission.

RESULTS

A graphical practical guide for several steps in diagnosing, identifying potential triggers and adequate treatment of persistent gastrointestinal symptoms in IBD in remission is provided based on supporting literature. The first part of this review focuses on the diagnostic and treatment approaches for potential IBD-related complications and comorbidities. The second part describes the approach to IBS-like symptoms in IBD in remission.

CONCLUSIONS

Persistent gastrointestinal symptoms in IBD in remission can be traced back to potential pathophysiological mechanisms in individual patients and can be treated adequately. For both IBD-related complications and comorbidities and IBS-like symptoms in IBD in remission, pharmacological, dietary, lifestyle or psychological treatments can be effective. A systematic and personalised approach is required to reduce the burden for patients, healthcare systems, and society.

Critical appraisal of the SIBO hypothesis and breath testing: A clinical practice update endorsed by the European society of neurogastroenterology and motility (ESNM) and the American neurogastroenterology and motility society (ANMS)

BACKGROUND

There is compelling evidence that microbe-host interactions in the intestinal tract underlie many human disorders, including disorders of gut-brain interactions (previously termed functional bowel disorders), such as irritable bowel syndrome (IBS). Small intestinal bacterial overgrowth (SIBO) has been recognized for over a century in patients with predisposing conditions causing intestinal stasis, such as surgical alteration of the small bowel or chronic diseases, including scleroderma and is associated with diarrhea and signs of malabsorption. Over 20 years ago, it was hypothesized that increased numbers of small intestine bacteria might also account for symptoms in the absence of malabsorption in IBS and related disorders. This SIBO-IBS hypothesis stimulated significant research and helped focus the profession's attention on the importance of microbe-host interactions as a potential pathophysiological mechanism in IBS.

PURPOSE

However, after two decades, this hypothesis remains unproven. Moreover, it has led to serious unintended consequences, namely the widespread use of unreliable and unvalidated breath tests as a diagnostic test for SIBO and a resultant injudicious use of antibiotics. In this review, we examine why the SIBO hypothesis remains unproven and, given the unintended consequences, discuss why it is time to reject this hypothesis and its reliance on breath testing. We also examine recent IBS studies of bacterial communities in the GI tract, their composition and functions, and their interactions with the host. While these studies provide important insights to guide future research, they highlight the need for further mechanistic studies of microbe-host interactions in IBS patients before we can understand their possible role in diagnosis and treatment of patient with IBS and related disorders.

Do Herbal Supplements and Probiotics Complement Antibiotics and Diet in the Management of SIBO? A Randomized Clinical Trial

Small intestinal bacterial overgrowth (SIBO) arises from dysbiosis in the small intestine, manifesting with abdominal symptoms. This study aims to assess the efficacy of combined antibiotic therapy, herbal supplements, probiotics, and dietary modifications in SIBO management. A total of 179 SIBO-diagnosed patients underwent clinical evaluation and breath testing. Patients were categorized into hydrogen (H2-SIBO) and methane (CH4-SIBO) groups. The control group received standard antibiotic therapy and a low-FODMAP diet, while the intervention group received additional herbal antibiotics, probiotics, and prebiotics. After treatment, both groups exhibited reduced gas levels, particularly in CH4-SIBO. Clinical remission rates were higher in the intervention group, especially in CH4-SIBO cases. Logistic regression analysis showed gas concentrations at diagnosis as significant predictors of treatment success. In conclusion, adjunctive herbal supplements and probiotics did not significantly impact gas levels, but showed potential for clinical improvement, especially in CH4-SIBO.

Intestinal microbiota regulates the gut-thyroid axis: the new dawn of improving Hashimoto thyroiditis

Intestinal microbiota plays an indispensable role in the host's innate immune system, which may be related to the occurrence of many autoimmune diseases. Hashimoto thyroiditis (HT) is one of the most common autoimmune diseases, and there is plenty of evidence indicating that HT may be related to genetics and environmental triggers, but the specific mechanism has not been proven clearly. Significantly, the composition and abundance of intestinal microbiota in patients with HT have an obvious difference. This phenomenon led us to think about whether intestinal microbiota can affect the progress of HT through some mechanisms. By summarizing the potential mechanism of intestinal microflora in regulating Hashimoto thyroiditis, this article explores the possibility of improving HT by regulating intestinal microbiota and summarizes relevant biomarkers as therapeutic targets, which provide new ideas for the clinical diagnosis and treatment of Hashimoto thyroiditis.

Diagnosis by Microbial Culture, Breath Tests and Urinary Excretion Tests, and Treatments of Small Intestinal Bacterial Overgrowth

Small intestinal bacterial overgrowth (SIBO) is characterized as the increase in the number and/or alteration in the type of bacteria in the upper gastrointestinal tract and accompanies various bowel symptoms such as abdominal pain, bloating, gases, diarrhea, and so on. Clinically, SIBO is diagnosed by microbial culture in duodenum/jejunum fluid aspirates and/or the breath tests (BT) of hydrogen/methane gases after ingestion of carbohydrates such as glucose. The cultural analysis of aspirates is regarded as the golden standard for the diagnosis of SIBO; however, this is invasive and is not without risk to the patients. BT is an inexpensive and safe diagnostic test but lacks diagnostic sensitivity and specificity depending on the disease states of patients. Additionally, the urinary excretion tests are used for the SIBO diagnosis using chemically synthesized bile acid conjugates such as cholic acid (CA) conjugated with para-aminobenzoic acid (PABA-CA), ursodeoxycholic acid (UDCA) conjugated with PABA (PABA-UDCA) or conjugated with 5-aminosalicylic acid (5-ASA-UDCA). These conjugates are split by bacterial bile acid (cholylglycine) hydrolase. In the tests, the time courses of the urinary excretion rates of PABA or 5-ASA, including their metabolites, are determined as the measure of hydrolytic activity of intestinal bacteria. Although the number of clinical trials with this urinary excretion tests is small, results demonstrated the usefulness of bile acid conjugates as SIBO diagnostic substrates. PABA-UDCA disulfate, a single-pass type unabsorbable compound without the hydrolysis of conjugates, was likely to offer a simple and rapid method for the evaluation of SIBO without the use of radioisotopes or expensive special apparatus. Treatments of SIBO with antibiotics, probiotics, therapeutic diets, herbal medicines, and/or fecal microbiota transplantation are also reviewed.

The Apparent Asymmetrical Relationship Between Small Bowel Bacterial Overgrowth, Endotoxemia, and Liver Steatosis and Fibrosis in Cirrhotic and Non-Cirrhotic Patients: A Single-Center Pilot Study

Introduction

Gut microbiota are a complex ecosystem harboring our intestine. They maintain human body equilibrium, while their derangement, namely, “dysbiosis“, has been associated with several gastrointestinal diseases, such as liver steatosis (NAFLD) and liver cirrhosis. Small intestinal bacterial overgrowth (SIBO) is an example of dysbiosis of the upper gastrointestinal (GI) tract.

Aim

The aim of this study is to evaluate the relationship between SIBO and levels of endotoxemia and grade of liver steatosis (LS) and liver fibrosis (LF) in hepatologic patients.

Materials and Methods

Consecutive outpatients referred to our hepatology clinic were tested for SIBO by the lactulose breath test (LBT) and peripheral blood levels of endotoxemia; LS grading and LF were assessed by abdominal ultrasound and transient elastography, respectively.

Results

Fifty-two consecutive patients (17 with alcohol abuse (4.5 ± 0.8 alcohol units per day), 4 with HCV and 2 with HBV infection, 24 of metabolic origin, 2 of autoimmune origin, and 3 with cholangiopathies; mean age 54.7 ± 8.3 years, 31 F, BMI 24.1 ± 1.1 Kg/m²) and 14 healthy volunteers (HV) (mean age 50.1 ± 4.3 years, 9 F, BMI 23.3 ± 1.1 Kg/m²) were enrolled. SIBO prevalence was significantly higher in cirrhotic (LC) vs. non-cirrhotic (LNC) patients and vs. HV (all, p < 0.05), with a significant positive trend according to Child-Pugh status (all, p < 0.05). SIBO prevalence was not correlated with LS stages (all, p = NS). Consensually, endotoxin levels were significantly higher in LC vs. LNC and vs. HV (all, p < 0.05) and significantly correlated with LF in patients with LC, according to Child-Pugh status (all, p < 0.05).

Conclusion

This study shows that SIBO prevalence and relative endotoxin blood levels seem to be significantly associated with the grade of LF vs. LS in LC. SIBO is also present under pre-cirrhotic conditions, but its prevalence seems to correlate with liver disease irreversible derangement.

Efficacy of rifaximin in treating with small intestine bacterial overgrowth: a systematic review and meta-analysis

OBJECTIVES

Over the past decades, rifaximin has been used to treat with small intestinal bacterial overgrowth (SIBO), however, the true efficacy remains unknown. This systematic review and meta-analysis was performed to assess the safety and efficacy of rifaximin in treating with patients with SIBO.

METHODS

Embase, Pubmed, Cochrane Central Register of Controlled Trials, and Web of Science were searched from inception to April, 2021 for published randomized controlled trials (RCTs) and observational studies with or without comparable arms.

RESULTS

A total of 21 observational studies and 5 RCTs involving 874 patients were included. The overall eradication rate according to intention-to-treat analysis (ITT) was 59% (95% CI: 50 to 69%; I² = 90.69%) and to per protocol analysis (PP) 63% (95% CI: 53 to 72%; I² = 90.32%). For 5 RCTs included comparing the efficacy between rifaximin and placebo or active controls, there was no significant difference (n = 203, risk ratio = 1.14, 95%CI: 0.59 to 2.19, P = 0.15, I² = 38%). Subgroup analysis and meta-regression indicated a dose-dependent eradication rate of rifaximin for SIBO.

CONCLUSION

Rifaximin is effective and safe in eradicating SIBO, with a dose-dependent efficacy and commonly associated with the improvement of the gastrointestinal symptoms and underlying diseases.

[Chronic intestinal failure]

The term intestinal failure (IF) is understood as the transient or irreversible loss of the resorptive capacity of the bowels. This includes a multitude of diseases, some of which have anatomical causes and others functional causes. The functional capacity (absorption and motility) of the remaining digestive tract and the bacterial overgrowth and false colonization of the small bowel are of prognostic importance. After exclusion of pathological intestinal findings, such as stenosis and dilatation, initially conservative treatment is employed with the aim of intestinal adaptation. Before failure or complications, initially conservative surgery and then organ replacement by transplantation should be considered. The IF is a temporary or permanent condition. For adults a length of 100cm small bowel without the colon, 60cm still with continuity to the colon and 35cm small bowel with complete preservation of the colon including the ileocecal valve are potentially sufficient for intestinal autonomy.

[Functional Exams in the gastroenterology - new developments and tips for the common practice]

The functional gastrointestinal disorders (FGIDs) have a high prevalence and are associated with high healthcare costs. The diagnosis of these diseases could be difficult and require func-tional tests such as high-resolution manometry (HRM) of the esophagus, anorectal manometry and H2-Breathtests. Due to the COVID-19 Pandemic and the fear of infections there was a marked reduction in the number of performed exams in the last months - nevertheless some exams are necessary, in order to exclude or to diagnose important and dangerous diseases like Achalasia. Goal of this article is to present some new and relevant developments in the field. The HRM of the esophagus is the diagnostic standard for Achalasia, a rare clinical condi-tion associated to dysphagia - new European guidelines suggests a safe strategy in perform-ing the pneumatic dilatation.The intestinal methanogen overgrowth (IMO) is a clinical condition caused by a high production of methane in the small intestine due to overgrowth of Methanobrevibacter smithii, this condition could be in some patients associated with irritable bowel syndrome.

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.

Small Intestinal Bacterial Overgrowth: Comprehensive Review of Diagnosis, Prevention, and Treatment Methods

Small intestinal bacterial overgrowth (SIBO) is a commonly diagnosed gastrointestinal disorder affecting millions of individuals throughout the United States. It refers to a condition in which there is an excess and imbalance of small intestinal bacteria. Despite its prevalence, it remains underdiagnosed due to the invasive nature of diagnostic testing. Symptoms observed in SIBO, including abdominal distension, bloating, diarrhea, and gas formation, are nonspecific and can overlap with other gastrointestinal disorders. Frequently cited predisposing factors include gastric acid suppression, dysmotility, gastric bypass, and opioids. The diagnostic gold standard remains small bowel aspirate and culture. However, due to its invasive nature, it remains an unpopular method among patients and clinicians alike. Glucose and lactulose breath testing have become the go-to diagnostic method in clinical practice due to its noninvasive nature and low cost. Treatment is guided towards the eradication of bacteria in the small bowel and usually consists of a prolonged course of oral antibiotics. Due to recent advances in our understanding of the human microbiome, we are surely poised for a transformation in our approach to diagnosing and treating this condition.

The role of small intestinal bacterial overgrowth and false positive diagnosis of lactose intolerance in southwest Hungary-A retrospective observational study

Background

Lactose intolerance is a frequent gastrointestinal disease affecting 47% of the Eastern European population. Small intestinal bacterial overgrowth (SIBO) leads to carbohydrate malabsorption and therefore to false results during lactose breath and tolerance tests.

Objectives

We aimed to assess the prevalence of lactose maldigestion and intolerance in Hungary and to investigate the role of combined diagnostic method and testing for SIBO in reducing false results.

Methods

We retrospectively analyzed data from 264 adult symptomatic patients who underwent 50g lactose breath and tolerance tests in parallel over a one-year period at our center. A ≥20 ppm elevation of H₂ or less than 1.1 mmol/l rise of blood glucose was diagnostic for lactose maldigestion. Patients with maldigestion who had symptoms during the test were defined as lactose intolerant. Patients with an early (≤90 min) significant (≥20 ppm) rise of H₂ during lactose and/or lactulose breath tests were determined to have SIBO. Patients with slow/rapid oro-cecal transit and inappropriate preparation before the test were excluded.

Results

49.6% of the 264 patients had lactose maldigestion, and 29.5% had lactose intolerance. The most frequent symptom was bloating (22.7%), while 34.8% of the study population and 60% of the symptomatic patients had SIBO. In 9.1% and 9.8% of the patients, the lactose breath and tolerance test alone gave false positive result compared with the combined method. SIBO was present in 75% of the false positives diagnosed with breath test only.

Conclusions

The prevalence of lactose intolerance is lower in Hungary compared to the Eastern European value (29.5% vs 47%), so it is worth performing a population-based prospective analysis in this area. A combination of lactose breath and tolerance tests and the careful monitoring of results (with early H2 rise, lactulose breath test, etc.) can decrease the false cases caused by e.g. SIBO.

Effect of eradicating hydrogen-forming small intestinal bacterial overgrowth with rifaximin on body weight change

Hydrogen formed by small intestinal bacterial overgrowth in patients with non-constipated irritable bowel syndrome has an inverse relationship with obesity. However, the effect of eradicating small intestinal hydrogen-producing bacterial overgrowth on the body weight of these patients has not yet been reported. The aim of this study was to investigate body weight changes after eradicating small intestinal bacterial overgrowth with rifaximin treatment in patients with non-constipated irritable bowel syndrome.We reviewed the charts of patients with non-constipated irritable bowel syndrome who showed abdominal symptoms with documented lactulose hydrogen breath test results in order to diagnose small intestinal bacterial overgrowth. A total of 153 patients were enrolled in the study and divided into quartiles according to body mass index (BMI) and body weight.In the lowest body weight quartile, the BMI and body weight were significantly increased (0.4 kg/m, P = .038; 0.6 kg, P = .010, respectively) in patients with negative lactulose hydrogen breath tests after rifaximin treatment. However, there was no significant change in body weight in the other quartiles. Despite treatment with rifaximin for 12 weeks, there was no change in BMI or body weight in any group of patients with consistently positive lactulose hydrogen breath tests.Eradication of hydrogen formed by small intestinal bacterial overgrowth does not cause clinically significant changes in body weight.

Small Intestinal Bacterial Overgrowth in Patients With Cirrhosis

Small intestinal bacterial overgrowth (SIBO) is defined by increased density and/or abnormal composition of microbiota in the small bowel. SIBO is often encountered in patients with cirrhosis as a result of impaired intestinal motility and delayed transit time, both of which are exacerbated by more severe liver disease. Additional risk factors for SIBO commonly encountered in cirrhotic patients include coexisting diabetes, autonomic neuropathy, and/or alcoholic use. Diagnosis of SIBO is performed by breath testing or jejunal aspiration, the gold standard. In cirrhotic patients, the presence of SIBO can lead to profound clinical consequences. Increased intestinal permeability in these patients predisposes to bacterial translocation into the systemic circulation. As a result, SIBO is implicated as a significant risk factor in the pathogenesis of both spontaneous bacterial peritonitis and hepatic encephalopathy in cirrhotics. Antibiotics, especially rifaximin, are the best studied and most effective treatment options for SIBO. However, prokinetics, probiotics, nonselective beta-blockers, and treatment of underlying liver-related pathophysiology with transjugular intrahepatic portosystemic shunt placement or liver transplantation are also being investigated. This review will discuss the risk factors, diagnosis, manifestations in cirrhosis, and treatment options of SIBO.

Effects of Rifaximin on Central Responses to Social Stress-a Pilot Experiment

Probiotics that promote the gut microbiota have been reported to reduce stress responses, and improve memory and mood. Whether and how antibiotics that eliminate or inhibit pathogenic and commensal gut bacteria also affect central nervous system functions in humans is so far unknown. In a double-blinded randomized study, 16 healthy volunteers (27.00 ± 1.60 years; 9 males) received either rifaximin (600 mg/day) (a poorly absorbable antibiotic) or placebo for 7 days. Before and after the drug intervention, brain activities during rest and during a social stressor inducing feelings of exclusion (Cyberball game) were measured using magnetoencephalography. Social exclusion significantly affected (p < 0.001) mood and increased exclusion perception. Magnetoencephalography showed brain regions with higher activations during exclusion as compared to inclusion, in different frequency bands. Seven days of rifaximin increased prefrontal and right cingulate alpha power during resting state. Low beta power showed an interaction of intervention (rifaximin, placebo) × condition (inclusion, exclusion) during the Cyberball game in the bilateral prefrontal and left anterior cingulate cortex. Only in the rifaximin group, a decrease (p = 0.004) in power was seen comparing exclusion to inclusion; the reduced beta-1 power was negatively correlated with a change in the subjective exclusion perception score. Social stress affecting brain functioning in a specific manner is modulated by rifaximin. Contrary to our hypothesis that antibiotics have advert effects on mood, the antibiotic exhibited stress-reducing effects similar to reported effects of probiotics (supported by NeuroGUT, a EU 7th Framework Programme ITN no. 607652; ClinicalTrials.gov identifier number NCT02793193).

Diagnostic criteria, severity classification and guidelines of systemic sclerosis

Several effective drugs have been identified for the treatment of systemic sclerosis (SSc). However, in advanced cases, not only their effectiveness is reduced but they may be also harmful due to their side-effects. Therefore, early diagnosis and early treatment is most important for the treatment of SSc. We established diagnostic criteria for SSc in 2003 and early diagnostic criteria for SSc in 2011, for the purpose of developing evaluation of each organ in SSc. Moreover, in November 2013, the American College of Rheumatology and the European Rheumatology Association jointly developed new diagnostic criteria for increasing their sensitivity and specificity, so we revised our diagnostic criteria and severity classification of SSc. Furthermore, we have revised the clinical guideline based on the newest evidence. In particular, the clinical guideline was established by clinical questions based on evidence-based medicine according to the New Minds Clinical Practice Guideline Creation Manual (version 1.0). We aimed to make the guideline easy to use and reliable based on the newest evidence, and to present guidance as specific as possible for various clinical problems in treatment of SSc.

Rediscover the clinical value of small intestinal bacterial overgrowth in patients with intestinal Behçet's disease

BACKGROUND AND AIMS

Many patients with intestinal Behçet's disease (BD) still suffer from gastrointestinal symptoms despite the disease being in endoscopic or radiological remission. Previous studies report that small intestinal bacterial overgrowth (SIBO) can be associated with inflammatory bowel disease. However, there have been no reports about SIBO in patients with intestinal BD. We sought to identify the frequency of SIBO in patients with inactive intestinal BD by hydrogen breath test (HBT) and to investigate the efficacy of rifaximin as a treatment for SIBO.

METHODS

Twenty-five patients with intestinal BD who had gastrointestinal symptoms even in endoscopic or radiological remission status were enrolled between January 2012 and January 2016. The patients filled out a questionnaire regarding their subjective gastrointestinal symptoms and took an HBT. Patients with positive HBT results were recommended to take 800-mg rifaximin daily for 14 days.

RESULTS

Nine patients (9/25, 36%) had a positive HBT test. Eight (8/9, 88.9%) were women, and their mean age was 48.7 years. The most common symptom was abdominal distension (8/9, 88.9%), followed by abdominal discomfort (6/9, 66.7%). Rifaximin was prescribed to the nine patients with positive HBT, but two patients refused to take the medication. Four weeks later, six of the seven patients taking rifaximin (85.7%) reported symptom improvement, and none of them reported adverse events.

CONCLUSIONS

More than one-third of the patients with inactive intestinal BD who had gastrointestinal symptoms were accompanied by SIBO using HBT. Rifaximin might be an effective and safe drug to treat these patients.

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.

Emergence of rifampin-resistant staphylococci after rifaximin administration in cirrhotic patients

Objectives

Rifaximin, a poorly absorbed antibiotics, has gut-specific therapeutic effects. Although frequently prescribed to manipulate intestinal luminal bacterial population in various diseases, the possible induction of antibacterial cross-resistance to a target pathogen is a major concern in long-term rifaximin administration. We aimed to evaluate whether rifampin-resistant staphylococci could evolve after rifaximin treatment in cirrhotic patients.

Method

A total of 25 cirrhotic patients who were administered rifaximin for the prevention of hepatic encephalopathy were enrolled. Swabs from both hands and the perianal skin were acquired on day 0 (before rifaximin treatment), period 1 (1–7 weeks after treatment), and period 2 (8–16 weeks after treatment) the staphylococcal strain identification and rifampin-resistance testing.

Results

A total of 198 staphylococcal isolates from 15 species were identified. Staphylococcus epidermidis was isolated most frequently, and Staphylococcus haemolyticus was the most common resistant species both from hands and perianal skin. Eleven patients (44.0%) developed rifampin-resistant staphylococcal isolates in period 1. Among these patients, only six (54.5%) were found to have rifampin-resistant isolates in period 2, with no significant infectious events. Rifampin-resistant staphylococcal isolates were more frequently found in perianal skin than from the hands. No patients acquired a newly resistant strain in period 2.

Conclusions

About one-half of cirrhotic patients in this study developed rifampin-resistant staphylococcal isolates after rifaximin treatment. Although the resistant strains were no longer detected in about half of the patients in the short-term, the long-term influence of this drug treatment should be determined.

Systematic review with meta-analysis: rifaximin is effective and safe for the treatment of small intestine bacterial overgrowth

BACKGROUND

Small intestinal bacterial overgrowth (SIBO) is a heterogeneous syndrome, characterised by an increased number and/or abnormal type of bacteria in the small bowel. Over the past decades, rifaximin has gained popularity for this indication despite its use is not evidence based.

AIM

To perform a systematic review and meta-analysis to summarise evidence about the efficacy and safety of rifaximin to eradicate SIBO in adult patients.

METHODS

MEDLINE, EMBASE, CCRCT, Scopus and Web of Science were searched from inception to March 16, 2015 for RCTs and observational studies. Furthermore, abstract books of major European, American and Asian gastroenterological meetings were also examined.

RESULTS

Thirty-two studies involving 1331 patients were included. The overall eradication rate according to intention-to-treat analysis was 70.8% (95% CI: 61.4-78.2; I² = 89.4%) and to per protocol analysis 72.9% (95% CI: 65.5-79.8; I² = 87.5%). Meta-regression identified three covariates (drug dose, study design and co-therapy) independently associated with an increased eradication rate. The overall rate of adverse events was 4.6% (95% CI: 2.3-7.5; I² = 63.6%). In the subset of studies (n= 10) allowing the analysis, improvement or resolution of symptoms in patients with eradicated SIBO was found to be 67.7% (95% CI: 44.7-86.9; I² = 91.3%).

CONCLUSIONS

Rifaximin treatment seems to be effective and safe for the treatment of SIBO. However, the quality of the available studies is generally poor. Well-designed RCTs are needed to substantiate these findings and to establish the optimal regimen.

Small Intestinal Bacterial Overgrowth and Other Intestinal Disorders

Gut microbiota is the largest organ of the human body. Although growth of bacteria more than 10⁵ colony forming unit (CFU) per milliliter in culture of upper gut aspirate is used to diagnosis small intestinal bacterial overgrowth (SIBO), 10³ CFU or more is being considered to suggest the diagnosis, particularly if colonic type bacteria are present in the upper gut. Although neither very sensitive nor specific, hydrogen breath tests are widely used to diagnose SIBO. Rifaximin is the best treatment for SIBO due to its broad spectrum, lack of systemic absorption, and safety profile.

Diagnosis and treatment of small intestinal bacterial overgrowth

A huge number of bacteria are hosted in the gastrointestinal tract, following a gradient increasing towards the colon. Gastric acid secretion and intestinal clearance provide the qualitative and quantitative partitioning of intestinal bacteria; small intestinal bacteria overgrowth (SIBO) occurs when these barrier mechanisms fail. Diagnosis of SIBO is challenging due to the low specificity of symptoms, the frequent association with other diseases of the gastrointestinal tract and the absence of optimal objective diagnostic tests. The therapeutic approach to SIBO is oriented towards resolving predisposing conditions, and is supported by antibiotic treatment to restore the normal small intestinal microflora and by modifications of dietary habits for symptomatic relief. In the near future, metagenomics and metabolomics will help to overcome the uncertainties of SIBO diagnosis and the pitfalls of therapeutic management, allowing the design of a personalized strategy based on the direct insight into the small intestinal microbial community.

Use of rifaximin in gastrointestinal and liver diseases

Rifaximin is a broad spectrum oral antibiotic with antimicrobial activity against Gram-positive and Gram-negative aerobic and anaerobic bacteria. It is poorly absorbed and thus has a highly favorable safety profile. Rifaximin has been shown to be effective in the treatment of traveler’s diarrhea, functional bloating and irritable bowel syndrome, small bowel bacterial overgrowth and in the prevention of recurrent overt hepatic encephalopathy. In addition, there is emerging evidence for a possible beneficial effect of rifaximin in the treatment of uncomplicated diverticular disease and in the prevention of recurrent diverticulitis. The use of rifaximin is associated with a low incidence of development, or persistence of spontaneous bacterial mutants. Moreover, the development of important drug resistance among extra-intestinal flora during rifaximin therapy is unlikely because of minimal systemic absorption and limited cross-resistance of rifaximin with other antimicrobials. This review addresses the current and emerging role of rifaximin in the treatment of gastrointestinal and liver disorders.

Limited prolonged effects of rifaximin treatment on irritable bowel syndrome-related differences in the fecal microbiome and metabolome

Irritable bowel syndrome (IBS) is a chronic functional disorder and its development may be linked, directly and indirectly, to intestinal dysbiosis. Here we investigated the interactions between IBS symptoms and the gut microbiome, including the relation to rifaximin (1200 mg daily; 11.2 g per a treatment). We recruited 72 patients, including 31 with IBS-D (diarrhea), 11 with IBS-C (constipation), and 30 with IBS-M (mixed constipation and diarrhea) and 30 healthy controls (HCs). Of them, 68%, 64%, and 53% patients with IBS-D, IBS-C, and IBS-M, respectively, achieved 10-12 week-term improvement after the rifaximin treatment. Stool samples were collected before and after the treatment, and fecal microbiotic profiles were analyzed by deep sequencing of 16S rRNA, while stool metabolic profiles were studied by hydrogen 1-nuclear magnetic resonance ((1)H-NMR) and gas chromatography-mass spectrometry (GC-MS). Of 26 identified phyla, only Bacteroidetes, Firmicutes, Proteobacteria, and Actinobacteria were consistently found in all samples. Bacteroidetes was predominant in fecal samples from HCs and IBS-D and IBS-M subjects, whereas Firmicutes was predominant in samples from IBS-C subjects. Species richness, but not community diversity, differentiated all IBS patients from HCs. Metabolic fingerprinting, using NMR spectra, distinguished HCs from all IBS patients. Thirteen metabolites identified by GC-MS differed HCs and IBS patients. However, neither metagenomics nor metabolomics analyses identified significant differences between patients with and without improvement after treatment.

Rifaximin combined with polymyxins: A potential regimen for selective decontamination of multidrug-resistant bacteria in the digestive tract?

Selective decontamination of the digestive tract (SDD) using combinations of oral non-absorbable antibiotics has been proposed as a means of preventing multidrug-resistant (MDR) infections. The minimum inhibitory concentrations (MICs) of rifaximin (RIFAX) were determined against 262 Gram-negative and Gram-positive bacterial isolates by broth microtitre assay. Rifampicin (RIF) was used as a comparator in the analysis. Synergistic interactions between RIFAX and polymyxin B (PMB) were assessed by using the chequerboard method and calculating the fractional inhibitory concentration index (FICI). The antimicrobial activities of both RIFAX and RIF were similar with little variation in the overall MIC distributions for Gram-negative non-fermenters and Gram-positive bacteria. However, against Enterobacteriaceae higher MICs (>16mg/L) were observed for RIFAX than for RIF (50% vs 27%). Amongst the 262 isolates tested, 100 could be considered resistant to RIFAX. Overall, the combination of RIFAX and PMB was more active against all of the isolates tested compared with either drug alone, with reductions of 2-11 doubling dilutions in individual MICs. Potent synergy was observed with the RIFAX+PMB combination using FICI criteria (FICI range 0.02-0.5). The data presented here suggest that combination therapy may be significantly more effective against isolates with RIFAX and/or PMB resistance and could be considered as part of a SDD regimen aimed at reducing enteric carriage of MDR pathogens in colonised and infected patients.

Rifaximin for the treatment of irritable bowel syndrome - a drug safety evaluation

INTRODUCTION

Irritable bowel syndrome is a functional gastrointestinal disorder with a multifactorial etiology. Alterations of intestinal motility and immunity, gut-brain interactions, as well as gut microbiota dysbiosis contribute to the development of irritable bowel syndrome. Therefore, gut microbiota modulation by non-absorbable antibiotics is a therapeutic option in patients with IBS.

AREAS COVERED

Published articles including patients with irritable bowel syndrome reporting data about rifaximin activity and safety have been searched throughout the literature and selected.

EXPERT OPINION

The optimal antibiotic molecule should be local-acting, long-acting and safe-acting. Rifaximin is a non-absorbable antibiotic with additional anti-inflammatory and gut microbiota-modulating activity. It is effective in inducing symptoms relief in patients with IBS, even after repeated treatment courses. Rifaximin-related side effects in patients with IBS are reported to be mild and infrequent; microbial resistance is rare and transient, due to the high local concentration of the drug and to the absence of horizontal transmission. Clostridium difficile infection is not usual in patients receiving rifaximin in absence of predisposing conditions such as hospitalization and immunosuppression, which are uncommon in patients affected by irritable bowel syndrome. Nevertheless rifaximin is an antibiotic active against Clostridium difficile infection. Rifaximin has limited metabolic interactions and is not expected to interfere with drug metabolism in patients with normal hepatic function. These properties make rifaximin a safe antibiotic for gut microbiota modulation in patients with IBS.

Refining small intestinal bacterial overgrowth diagnosis by means of carbohydrate specificity: a proof-of-concept study

BACKGROUND

Diagnosis of small intestinal bacterial overgrowth (SIBO) remains challenging. This study aimed at proving the diagnostic concept of carbohydrate-specific SIBO (cs-SIBO) using glucose, fructose and sorbitol hydrogen (H2)/methane (CH4) breath testing (HMBT).

METHODS

In this study 125 patients referred to our outpatient clinic for SIBO testing were included. All individuals underwent glucose (50 g), fructose (25 g) and sorbitol (12.5 g) HMBT at 3 consecutive days. Patients with cs-SIBO (i.e. early H2/CH4 peak) were given rifaximin (600 mg/day) in a 10-day treatment. HMBT results were reassessed in a subset of patients 3-6 months after antibiotic therapy. In view of cs-SIBO diagnosis, agreements between HMBT results obtained for different sugars were calculated using Cohen's kappa (κ) with 95% confidence intervals (CIs).

RESULTS

A total of 59 (47.2%) patients presented an early H2/CH4 peak with one or more sugars. Among these, 21 (16.8%), 10 (8.0%) and 7 (5.6%) individuals had a positive HMBT result with either glucose, fructose or sorbitol, respectively. Another 21 (16.8%) patients with a positive glucose HMBT result were also found positive with an early H2/CH4 peak obtained after ingestion of fructose and/or sorbitol. Fair agreement was observed between glucose and fructose (κ = 0.26, p = 0.0018) and between glucose and sorbitol (κ = 0.18, p = 0.0178) HMBT results. Slight agreement was observed between fructose and sorbitol (κ = 0.03, p = 0.6955) HMBT results only. Successful antibiotic therapy with rifaximin could be demonstrated in 26/30 (86.7%) of patients as indicated by normal HMBT results and symptom remission.

CONCLUSIONS

Combined glucose, fructose and sorbitol HMBT has the potential to optimize cs-SIBO diagnosis. Furthermore, the majority of patients with cs-SIBO seem to benefit from rifaximin therapy regardless of its carbohydrate specificity.

New and emerging therapies for the treatment of irritable bowel syndrome: an update for gastroenterologists

Irritable bowel syndrome is a functional bowel disorder with gastrointestinal symptoms (e.g. abdominal pain, straining, urgency, incomplete evacuation, nausea, and bloating) that occur alongside bowel function alterations (i.e. constipation, diarrhea, or both). Patients with irritable bowel syndrome may also experience comorbid anxiety and depression. Irritable bowel syndrome is common, with a prevalence estimated between 3% and 28%, affecting patient health and quality of life. Patients with moderate or severe irritable bowel syndrome generally seek medical care, whereas those with milder symptoms may choose self-management. Most patients with irritable bowel syndrome receive outpatient care, but irritable bowel syndrome-related hospitalizations do occur. The pathophysiology of irritable bowel syndrome is multifactorial (i.e. genetics, immune components, changes in the gut microbiota, disturbances in physiologic stress response systems, and psychosocial factors). Management of irritable bowel syndrome can include lifestyle changes, dietary interventions, counseling, psychologic medication, and agents that affect gastrointestinal motility. A number of therapies have emerged in recent years with clinical trial data demonstrating efficacy and safety for patients with irritable bowel syndrome, including agents that target gastrointestinal motility (i.e. linaclotide), gastrointestinal opioid receptors (i.e. asimadoline, eluxadoline), and gut microbiota (i.e. rifaximin). Linaclotide has been shown to significantly improve stool frequency and abdominal pain compared with placebo in constipation-predominant irritable bowel syndrome (number needed to treat, 5.1). Asimadoline shows efficacy in patients with moderate-to-severe irritable bowel syndrome-related pain. Rifaximin provided adequate relief of global irritable bowel syndrome symptoms versus placebo for a significantly greater percentage of patients with diarrhea-predominant irritable bowel syndrome (p < 0.001). Management that encompasses all aspects of irritable bowel syndrome (gastrointestinal symptoms) and comorbid psychologic symptoms (e.g. anxiety or depression) is important for improving overall patient health and well-being.

Atopic dermatitis and the intestinal microbiota in humans and dogs

The prevalence of human and canine allergic diseases is commonly perceived to be increasing. Suggested predisposing factors in people and dogs include increased allergen load, increased exposure to pollutants, reduced family size, reduced microbial load and less exposure to infection at a young age, increasingly urbanised environment, and changes in dietary habits. Genetic make‐up may provide a template for phenotypic predisposition which is strongly influenced by our diet and environment leading to constant regulation of gene expression. One way in which diet can alter gene expression is via its effects on the gut flora or microbiota, the collection of microbes residing in the gastrointestinal tract. The resident microbiota is important in maintaining structural and functional integrity of the gut and in immune system regulation. It is an important driver of host immunity, helps protect against invading enteropathogens, and provides nutritional benefits to the host. Disruption of the microbiota (dysbiosis) may lead to severe health problems, both in the gastrointestinal tract and extra‐intestinal organ systems. The precise mechanisms by which the intestinal microbiota exerts its effects are only beginning to be unravelled but research is demonstrating close links between gut microflora and many factors involved in the pathogenesis of atopic dermatitis (AD). AD and indeed any other ‘skin disease’, may be seen as a possible manifestation of a more systemic problem involving gut dysbiosis and increased intestinal permeability, which may occur even in the absence of gastrointestinal signs. Manipulation of the canine intestinal microbiota as a method for modifying atopy, may be attempted in many ways including avoidance of certain foods, supplementation with probiotics and prebiotics, optimising nutrient intake, minimising stress, antimicrobial therapy, correction and prevention of low stomach acid, and faecal microbiota transplantation (FMT).

Modulation of the gut microbiota composition by rifaximin in non-constipated irritable bowel syndrome patients: a molecular approach

Rifaximin, with its low systemic absorption, may represent a treatment of choice for irritable bowel syndrome (IBS), mainly due to its ability to act on IBS pathogenesis, through the influence on gut microbiota. The aim of the present study was to assess, by biomolecular tools, the rifaximin active modulation exerted on gut microbiota of non-constipated IBS patients. Fifteen non-constipated IBS subjects were treated with 550 mg rifaximin three times a day for 14 days. Stool samples were collected before starting the treatment, at the end of it, and after a 6-week washout period. Real-time polymerase chain reaction, denaturing gradient gel electrophoresis, and next-generation sequencing were applied to all the samples to verify and quantify possible microbial fluctuations. Rifaximin treatment did not affect the overall composition of the microbiota of the treated subjects, inducing fluctuations in few bacterial groups, balanced by the replacement of homologs or complementary bacterial groups. Rifaximin appeared to influence mainly potentially detrimental bacteria, such as Clostridium, but increasing the presence of some species, such as Faecalibacterium prausnitzii. A decrease in the Firmicutes/Bacteroidetes ratio after 14 days of treatment and bacterial profiles with higher biodiversity were observed during the follow-up compared to baseline. Rifaximin treatment, although effective on IBS symptom relief and normalization of lactulose breath test, did not induce dramatic shifts in the microbiota composition of the subjects, stimulating microbial reorganization in some populations toward a more diverse composition. It was not possible to speculate on differences of fecal microbiota modification between responders vs nonresponders and to correlate the quali-/quantitative modification of upper gastrointestinal microbiota and clinical response.

Determination of rifaximin treatment period according to lactulose breath test values in nonconstipated irritable bowel syndrome subjects

Small intestinal bacterial overgrowth (SIBO) can partly explain irritable bowel syndrome (IBS), and rifaximin has been observed to improve abdominal symptoms in nonconstipated IBS patients. However, there are few reports on the association of the rifaximin treatment periods with the results of a lactulose breath test (LBT). Therefore, we performed a retrospective review of patient charts to investigate the relation between the rifaximin treatment periods with LBT results in nonconstipated IBS patients. We also evaluated the time to achieve a symptomatic improvement in the IBS patients as compared to the changes in the LBT. We reviewed the charts for patients who showed IBS symptoms with documented positive results for LBT during their initial visit and who had a follow-up LBT after treatment with rifaximin. The LBT values were compared to the subjects' symptom scores. A total of 102 subjects had a follow-up LBT to assess LBT normalization. The subjects were divided into groups according to treatment periods of 4 weeks (n = 36), 8 weeks (n = 43), and 12 weeks (n = 23). The groups with a longer treatment exhibited an increase in the hydrogen gas value at 90 min and its sum during 90 min at the initial LBT. There were significant differences in hydrogen gas value at 90 min and in its sum during 90 min at the initial LBT between the groups treated for 4 and 12 weeks. The most significant treatment response was observed during the first 4 weeks for all treatment groups. Symptomatic improvement occurred earlier than LBT normalization in the treatment period over 4 weeks. The results indicate that different rifaximin treatment periods are needed in accordance with LBT levels to effectively eradicate SIBO.

[Motility disorders of the small intestine]

Chronic intestinal pseudo-obstruction (CIPO) is the most severe form of intestinal motility disorder, which leads to chronic or intermittent symptoms and signs of (sub-)ileus despite the absence of an intestinal obstruction. Small bowel motility disturbances may occur as primary diseases or secondary to a large number of other diseases and disturbances including rheumatological diseases and neurotoxic drugs. Pathological alterations affect the nervous system, smooth muscles, and/or mesenchymal structures such as the interstitial cells of Cajal or glia cells. Clinical symptoms are unspecific so that the initially suspected diagnosis is almost always wrong. Thus, extensive and stepwise diagnostic procedures are required involving specialized centers in order to exclude intestinal obstruction, to search for complications and potential causes of the disease, to quantify the extension and severity of the motility disorder, and to clarify the pathomechanism if possible. General therapeutic goals include maintenance of adequate nutritional status, improvement of propulsive motility, amelioration of abdominal symptoms, and avoidance and/or therapy of complications. Some CIPO patients require permanent parenteral nutrition. If this causes intolerable complications, small bowel transplantation can be considered in suitable patients as ultima ratio.

Rifaximin for prevention and treatment of hepatic encephalopathy

Hepatic encephalopathy (HE) is a serious neuropsychiatric syndrome of the central nervous system caused by liver failure or portosystemic shunt, seriously affecting patients' physical and mental well being. Although the pathogenesis of HE is still unclear at present, ammonia poisoning is believed to play a dominant role. Thus, reduction of ammonia is an important treatment for HE. This paper discusses the role of rifaximin in the prevention and treatment of HE.

Small intestinal bacterial overgrowth syndrome in children

Introduction

Small intestinal bacterial overgrowth syndrome (SIBO) is defined as an increased number of nonpathogenic bacteria over 10⁵ organisms in 1 millilitre of small intestine content. The most common predisposing factors include, among others, gut motility disorders and chronic use of proton pump inhibitors. The results of recent studies indicate the importance of SIBO in gastrointestinal diseases.

Aim

To assess the prevalence of SIBO in children with abdominal pain.

Material and methods

One hundred children (59 girls and 41 boys) aged from 4 to 17 years (mean age: 10.47 ±3.73 years), hospitalised due to abdominal pain, were enrolled in the study. Hydrogen breath test (HBT) with lactulose was established among all patients. Expired air was analysed using a Gastrolyzer (Bedfont).

Results

The HBT result was positive in 63 (63%) children with abdominal pain; including 40 girls (67.8%) and 23 boys (56.1%). The test was positive in the group of 29 (46%) children aged under 10 years and in the group of 34 (54%) children aged over 10 years. Among the patients who reported for the control study 88% achieved a normalisation of HBT after treatment.

Conclusions

The prevalence of positive HBT results in the group of patients with abdominal pain is over 60%. Small intestinal bacterial overgrowth syndrome should be considered as one of the causes of abdominal pain in children. The SIBO in children shows a good response to treatment.

Gastrointestinal involvement in systemic sclerosis

Systemic sclerosis is an autoimmune chronic disease characterised by microvascular, muscular and immunologic abnormalities that lead to progressive and systemic deposition of connective tissue in the skin and internal organs. The gastrointestinal tract is often overlooked by physicians but it is the most affected organ after the skin, from the mouth to the anus. Indeed, 80% of SSc patients may present with gastrointestinal involvement. Gastrointestinal manifestations range from bloating and heartburn to dysphagia and anorectal dysfunction to severe weight loss and malabsorption. However, the gastrointestinal involvement is rarely the direct cause of death, but has great impact on quality of life and leads to several comorbidities that subsequently affect patients' survival. Treatments, including nutritional support and prokinetics provide limited benefits and do not arrest the progressive course of the disease, but earlier detection of gastrointestinal involvement may reduce the risk of complications such as malnutrition.

Is rifaximin effective in maintaining remission in Crohn's disease?

BACKGROUND

Recent studies indicate that persistent intestinal inflammation in patients with Crohn's disease (CD) might be caused by abnormal intestinal microbiota. This hypothesis may suggest a beneficial effect of antibiotics in CD therapy. So far, guidelines do not recommend antibiotics except in the treatment of complicated CD, and there are few studies on the effects of rifaximin in these patients.

METHODS

Between December 2011 and December 2012, we performed a blinded randomized trial in 168 patients with a previous history of moderately active CD concerning the efficacy of rifaximin. All the patients had previously achieved remission with standard therapy (prednisone/budesonide). Data from patients receiving 800 mg of rifaximin (83 patients) twice a day for 12 weeks were compared with those from patients who received placebo (83 patients). The primary endpoint was maintaining remission during the follow-up.

RESULTS

All the patients (100%; 83/83) on 800 mg of rifaximin were in remission after 12 weeks of treatment in comparison with 84% (70/83) of the placebo group. This significant difference was also persistent at the 24-week follow-up [78% (65/83) vs. 41% (34/83), respectively]. The last evaluation performed at 48 weeks revealed disease activity in 45% (38/83) of the patients of the rifaximin group, i.e. a significant decrease compared with the placebo group [75% (63 of 83)].

CONCLUSIONS

Remission previously obtained with standard treatment can be sustained in patients with moderately active CD after the administration of 800 mg of rifaximin.

Herbal therapy is equivalent to rifaximin for the treatment of small intestinal bacterial overgrowth

OBJECTIVE

Patients with small intestine bacterial overgrowth (SIBO) have chronic intestinal and extraintestinal symptomatology which adversely affects their quality of life. Present treatment of SIBO is limited to oral antibiotics with variable success. A growing number of patients are interested in using complementary and alternative therapies for their gastrointestinal health. The objective was to determine the remission rate of SIBO using either the antibiotic rifaximin or herbals in a tertiary care referral gastroenterology practice.

DESIGN

One hundred and four patients who tested positive for newly diagnosed SIBO by lactulose breath testing (LBT) were offered either rifaximin 1200 mg daily vs herbal therapy for 4 weeks with repeat LBT post-treatment.

RESULTS

Three hundred ninety-six patients underwent LBT for suspected SIBO, of which 251 (63.4%) were positive 165 underwent treatment and 104 had a follow-up LBT. Of the 37 patients who received herbal therapy, 17 (46%) had a negative follow-up LBT compared to 23/67 (34%) of rifaximin users (P=.24). The odds ratio of having a negative LBT after taking herbal therapy as compared to rifaximin was 1.85 (CI=0.77-4.41, P=.17) once adjusted for age, gender, SIBO risk factors and IBS status. Fourteen of the 44 (31.8%) rifaximin non-responders were offered herbal rescue therapy, with 8 of the 14 (57.1%) having a negative LBT after completing the rescue herbal therapy, while 10 non-responders were offered triple antibiotics with 6 responding (60%, P=.89). Adverse effects were reported among the rifaximin treated arm including 1 case of anaphylaxis, 2 cases of hives, 2 cases of diarrhea and 1 case of Clostridium difficile. Only one case of diarrhea was reported in the herbal therapy arm, which did not reach statistical significance (P=.22).

CONCLUSION

SIBO is widely prevalent in a tertiary referral gastroenterology practice. Herbal therapies are at least as effective as rifaximin for resolution of SIBO by LBT. Herbals also appear to be as effective as triple antibiotic therapy for SIBO rescue therapy for rifaximin non-responders. Further, prospective studies are needed to validate these findings and explore additional alternative therapies in patients with refractory SIBO.

Microbiota, gastrointestinal infections, low-grade inflammation, and antibiotic therapy in irritable bowel syndrome: an evidence-based review

BACKGROUND

Post-infectious irritable bowel syndrome (PI-IBS) prevalence, small intestinal bacterial overgrowth (SIBO), altered microbiota, low-grade inflammation, and antibiotic therapy in IBS are all controversial issues.

AIMS

To conduct an evidence-based review of these factors.

METHODS

A review of the literature was carried out up to July 2012, with the inclusion of additional articles as far as August 2013, all of which were analyzed through the Oxford Centre for Evidence-Based Medicine (OCEBM) system.

RESULTS

1.There is greater SIBO probability in IBS when breath tests are performed, but prevalence varies widely (2-84%). 2.The gut microbiota in individuals with IBS is different from that in healthy subjects, but a common characteristic present in all the patients has not been established. 3.The incidence and prevalence of PI-IBS varies from 9-10% and 3-17%, respectively, and the latter decreases over time. Bacterial etiology is the most frequent but post-viral and parasitic cases have been reported. 4.A sub-group of patients has increased enterochromaffin cells, intraepithelial lymphocytes, and mast cells in the intestinal mucosa, but no differences between PI-IBS and non-PI-IBS have been determined. 5.Methanogenic microbiota has been associated with IBS with constipation. 6.Rifaximin at doses of 400mg TID/10days or 550mg TID/14days is effective treatment for the majority of overall symptoms and abdominal bloating in IBS. Retreatment effectiveness appears to be similar to that of the first cycle.

CONCLUSIONS

Further studies are required to determine the nature of the gut microbiota in IBS and the differences in low-grade inflammation between PI-IBS and non-PI-IBS. Rifaximin has shown itself to be effective treatment for IBS, regardless of prior factors.

Abdominal bloating: pathophysiology and treatment

Abdominal bloating is a very common and troublesome symptom of all ages, but it has not been fully understood to date. Bloating is usually associated with functional gastrointestinal disorders or organic diseases, but it may also appear alone. The pathophysiology of bloating remains ambiguous, although some evidences support the potential mechanisms, including gut hypersensitivity, impaired gas handling, altered gut microbiota, and abnormal abdominal-phrenic reflexes. Owing to the insufficient understanding of these mechanisms, the available therapeutic options are limited. However, medical treatment with some prokinetics, rifaximin, lubiprostone and linaclotide could be considered in the treatment of bloating. In addition, dietary intervention is important in relieving symptom in patients with bloating.

Meta-analysis: antibiotic therapy for small intestinal bacterial overgrowth

BACKGROUND

Small intestinal bacterial overgrowth (SIBO) is an under-recognised diagnosis with important clinical implications when untreated. However, the optimal treatment regimen remains unclear.

AIM

To perform a systematic review and meta-analysis comparing the clinical effectiveness of antibiotic therapies in the treatment of symptomatic patients with documented SIBO.

METHODS

Four databases were searched to identify clinical trials comparing effectiveness of: (i) different antibiotics, (ii) different doses of the same antibiotic and (iii) antibiotics compared with placebo. Data were independently extracted according to predetermined inclusion and exclusion criteria. Study quality was independently assessed. The primary outcome was normalisation of post-treatment breath testing. The secondary outcome was post-treatment clinical response.

RESULTS

Of 1356 articles identified, 10 met inclusion criteria. Rifaximin was the most commonly studied antibiotic (eight studies) with overall breath test normalisation rate of 49.5% (95% confidence interval, CI 44.0-55.1) (44.0%-55.1%) then (46.7%-55.5%), then (4.6%-17.8%). Antibiotic efficacy varied by antibiotic regimen and dose. Antibiotics were more effective than placebo, with a combined breath test normalisation rate of 51.1% (95% CI 46.7-55.5) for antibiotics compared with 9.8% (95% CI 4.6-17.8) for placebo. Meta-analysis of four studies favoured antibiotics over placebo for breath test normalisation with an odds ratio of 2.55 (95% CI 1.29-5.04). Clinical response was heterogeneously evaluated among six studies, but tended to correlate with breath test normalisation.

CONCLUSIONS

Antibiotics appear to be more effective than placebo for breath test normalisation in patients with symptoms attributable to SIBO, and breath test normalisation may correlate with clinical response. Studies were limited by modest quality, small sample size and heterogeneous design. Additional higher quality clinical trials of SIBO therapy are warranted.

Systemic sclerosis and the gut

Gastrointestinal involvement (GI) is increasingly recognized as a major cause of both morbidity and mortality in systemic sclerosis (SSc). GI complications are common, second only to skin involvement, and affect up to 90% of patients. Although treatment modalities have changed little for upper gut symptoms such as GI reflux, there are emerging treatment modalities for the common lower gut symptoms (constipation and fecal incontinence), which will be reviewed. The important link between reflux and interstitial lung disease in SSc is also addressed. The aim of this review is to help the clinician understand and manage GI symptoms in SSc.

Rifaximin in the treatment of irritable bowel syndrome: is there a high risk for development of antimicrobial resistance?

Irritable bowel syndrome (IBS), a chronic, nonfatal illness is commonly encountered in clinical practice; however, treatment options are limited and often ineffectual. Despite this, there is increasing evidence that bacterial overgrowth in the bowel (dysbiosis) may be an etiological factor in IBS. This has lead to studies in which the antibiotic agent rifaximin has been used to reduce the microbial burden in the bowel, to some extent alleviating the symptoms of IBS. Rifaximin is a member of the rifamycin class of antibiotics, which when administered orally has the distinctions of being gut specific coupled with poor systemic absorption, characteristics that are suggested to limit the development of bacterial resistance. The rifamycins are currently used to treat serious human diseases including tuberculosis, meningococcal disease, methicillin-resistant Staphylococcus aureus and Clostridium difficile infections. The use of rifamycins in the treatment of these diseases is associated with the development of antibiotic resistance over time. When considering the importance of the rifamycins in the treatment of serious human diseases, the large number of patients affected by IBS, and the lack of scientific evidence available on the development of antibiotic resistance to rifaximin over the long-term when used in the gut, it is advisable that the use of rifaximin as a therapy for IBS should be limited to single, acute, short-term treatment.

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.

Rifaximin therapy of irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder characterized by abdominal pain and altered bowel habits in the absence of specific organic pathology. Although the underlying pathogenesis of IBS is not well-understood, small intestinal bacterial overgrowth (SIBO) or other abnormalities in the gut flora is believed to contribute to the development of a subset of IBS cases. Rifaximin is a poorly absorbed antimicrobial with activity against enteric pathogens. A number of studies have shown a significant improvement in IBS symptoms with antibiotic therapy including rifaximin. In this review, we discuss the pharmacokinetics, in vitro susceptibility profile, and efficacy and safety data from clinical trials of rifaximin treatment of IBS.