Small Intestinal Bacterial Overgrowth in Patients with Irritable Bowel Syndrome: Clinical Characteristics, Psychological Factors, and Peripheral Cytokines. Gastroenterol Res Pract. 2016;2016:3230859. [PMID: 27379166 DOI: 10.1155/2016/3230859]

Low prevalence of positive hydrogen breath tests in patients with functional gastrointestinal conditions and hypermobile Ehlers-Danlos syndrome

BACKGROUND

Using hydrogen breath testing (HBT) to diagnose small intestinal bacterial overgrowth (SIBO) remains controversial in patients with functional gastrointestinal (GI) disorders, and unknown in those with hypermobility Ehlers-Danlos syndrome (hEDS). We assessed prevalence of positive HBTs in these groups, evaluated the predictive value of GI symptoms and the potential role of proton pump inhibitors (PPIs) on test results.

METHODS

Sequential patients referred for HBT to a tertiary unit were classified into the following groups: GI maldigestion/malabsorption, GI sensorimotor disorders, hEDS, and functional GI disorders. All underwent standardized HBT, and the yield was assessed against symptoms and PPI use.

KEY RESULTS

A total of 1062 HBTs were performed over 3 years (70% female, mean age 48 ± 16 years). Overall, 7.5% (80/1062) patients had a positive HBT. Prevalence of positive HBT was highest in patients with GI maldigestion/malabsorption (17.9%; DOR 16.16, p < 0.001), GI sensorimotor disorders (15.9%; DOR 8.84, p < 0.001), compared to functional GI disorders (1.6%; DOR 1.0) (p < 0.0001). None of the hEDS patients tested positive for HBT. A positive HBT was independently associated with increased age (DOR 1.03; p < 0.001) and symptoms of diarrhea (DOR 3.95; p < 0.0001). Patients on PPIs tended towards a positive HBT than patients off PPIs (16.1% vs 6.9%; DOR 2.47; p < 0.0001).

CONCLUSIONS & INFERENCES

Less than 2% of patients with functional GI disorders, and none of the patients with hEDS had a positive HBT. Pre-test probability was higher in patients with: GI structural or neurological disorders; use of long-term PPIs and symptoms of diarrhea. These criteria may be helpful in making appropriate therapeutic decisions and avoiding unnecessary hydrogen breath testing.

Epidemiology of small intestinal bacterial overgrowth

Small intestinal bacterial overgrowth (SIBO) is defined as an increase in the bacterial content of the small intestine above normal values. The presence of SIBO is detected in 33.8% of patients with gastroenterological complaints who underwent a breath test, and is significantly associated with smoking, bloating, abdominal pain, and anemia. Proton pump inhibitor therapy is a significant risk factor for SIBO. The risk of SIBO increases with age and does not depend on gender or race. SIBO complicates the course of a number of diseases and may be of pathogenetic significance in the development of their symptoms. SIBO is significantly associated with functional dyspepsia, irritable bowel syndrome, functional abdominal bloating, functional constipation, functional diarrhea, short bowel syndrome, chronic intestinal pseudo-obstruction, lactase deficiency, diverticular and celiac diseases, ulcerative colitis, Crohn’s disease, cirrhosis, metabolic-associated fatty liver disease (MAFLD), primary biliary cholangitis, gastroparesis, pancreatitis, cystic fibrosis, gallstone disease, diabetes, hypothyroidism, hyperlipidemia, acromegaly, multiple sclerosis, autism, Parkinson’s disease, systemic sclerosis, spondylarthropathy, fibromyalgia, asthma, heart failure, and other diseases. The development of SIBO is often associated with a slowdown in orocecal transit time that decreases the normal clearance of bacteria from the small intestine. The slowdown of this transit may be due to motor dysfunction of the intestine in diseases of the gut, autonomic diabetic polyneuropathy, and portal hypertension, or a decrease in the motor-stimulating influence of thyroid hormones. In a number of diseases, including cirrhosis, MAFLD, diabetes, and pancreatitis, an association was found between disease severity and the presence of SIBO. Further work on the effect of SIBO eradication on the condition and prognosis of patients with various diseases is required.

Personality, Anxiety, and Stress in Patients with Small Intestine Bacterial Overgrowth Syndrome. The Polish Preliminary Study

OBJECTIVE

Small intestinal bacterial overgrowth (SIBO) syndrome is associated with depression and anxiety. This study aimed to examine for the first time the correlation between personality traits, situational anxiety, and stress in Polish patients with SIBO.

METHODOLOGY

This study included 26 patients with SIBO aged 20-35 years and 24 non-SIBO patients aged 20-35 years. The following instruments were used: NEO-FFI Personality Inventory, KPS Sense of Stress Questionnaire, and the anxiety-state subscale from the State-Trait Anxiety Inventory (STAI).

RESULTS

Compared to the non-SIBO subgroup, SIBO patients expressed specific patterns of personality traits: higher neuroticism, lower extroversion, and a higher state of anxiety and stress. Unlike the non-SIBO subgroup, stress (total emotional tension, external, and intrapsychic) correlated negatively only with extroversion.

CONCLUSIONS

Personality is the primary regulator of experience and behavior. The specificity captured in the research is a premise for an in-depth study considering various psychological variables to determine cause-effect relationships.

Small Intestine Bacterial Overgrowth Can Form an Indigenous Proinflammatory Environment in the Duodenum: A Prospective Study

Small intestinal bacterial overgrowth (SIBO) contributes to the formation of an inflammatory environment in various intestinal and extraintestinal diseases. Cytokines that participate in these mechanisms are yet to be examined. Upper gastrointestinal endoscopy with duodenal aspiration was performed in 224 patients. Quantitative cultures of aerobic species were performed, concentrations of interleukin 1β (IL-1β), interleukin 6 (IL-6), and tumor necrosis factor alpha (TNF-α) were measured, and loads of Escherichia coli, Klebsiella pneumoniae, Methanobevibacter smithii, and Aeromonas spp. were detected via real-time PCR in the duodenal fluid. Analysis showed that the odds ratio (OR) for elevated IL-1β levels was 2.61 (1.06–6.43, p = 0.037) among patients with SIBO compared to patients without SIBO, while there was no significant difference at elevated IL-6 and TNF-α levels between patients with and without SIBO, using ≥10³ cfu/mL as a cut-off. The presence of all three elevated cytokine levels has OR 3.47 (1.06–11.34, p = 0.030) among patients with SIBO. Klebsiella pneumoniae detection was positively related with IL-6 and TNF-α levels, when Methanobevibacter smithii was positively related with IL-1β levels. The presence of SIBO is associated with elevated IL-1β levels in the duodenal fluid. There is a high prevalence of all three proinflammatory cytokine levels elevated (IL-1β, IL-6, and TNF-α) in the duodenal fluid among patients with SIBO.

Evidence of altered mucosa-associated and fecal microbiota composition in patients with Irritable Bowel Syndrome

Altered bacterial composition and small intestinal bacterial overgrowth (SIBO) may be associated with irritable bowel syndrome (IBS). This study aimed to determine the fecal and mucosa-associated bacterial composition along the gastrointestinal (GI) tract and to assess SIBO in IBS. Bacterial composition of feces, and mucosa of the duodenum and sigmoid colon was determined by 16S rRNA-amplicon-sequencing. SIBO was evaluated by bacterial culture of duodenal aspirate, glucose and lactulose breath tests. Mucosal antibacterial gene expression was assessed by PCR Array. The bacterial profiles of feces and the mucosa of sigmoid colon, but not duodenum, differed between IBS patients (n = 17) and HS (n = 20). The IBS specific bacterial profiles were linked to the colonic antibacterial gene expression. Fecal bacterial profile differed between IBS subtypes, while the mucosa-associated bacterial profile was associated with IBS symptom severity and breath tests results at baseline (H₂ and/or CH₄ ≥ 15 ppm). The prevalence of SIBO was similar between IBS patients and HS. This study demonstrates that alterations in the bacterial composition of the sigmoid colon of IBS patients were linked to symptoms and immune activation. While breath tests reflected the mucosa-associated bacterial composition, there was no evidence for high prevalence of SIBO or small intestinal bacterial alterations in IBS.

Small Intestinal Bacterial Overgrowth and Irritable Bowel Syndrome - An Update

Small intestinal bacterial overgrowth (SIBO) is one manifestation of gut microbiome dysbiosis and is highly prevalent in IBS (Irritable Bowel Syndrome). SIBO can be diagnosed either by a small bowel aspirate culture showing ≥10³ colony-forming units (CFU) per mL of aspirate, or a positive hydrogen lactulose or glucose breath test. Numerous pathogenic organisms have been shown to be increased in subjects with SIBO and IBS, including but not limited to Enterococcus, Escherichia coli, and Klebsiella. In addition, Methanobrevibacter smithii, the causal organism in a positive methane breath test, has been linked to constipation predominant irritable bowel syndrome (IBS-C). As M. smithii is an archaeon and can overgrow in areas outside of the small intestine, it was recently proposed that the term intestinal methanogen overgrowth (IMO) is more appropriate for the overgrowth of these organisms. Due to gut microbiome dysbiosis, patients with IBS may have increased intestinal permeability, dysmotility, chronic inflammation, autoimmunity, decreased absorption of bile salts, and even altered enteral and central neuronal activity. As a consequence, SIBO and IBS share a myriad of symptoms including abdominal pain, distention, diarrhea, and bloating. Furthermore, gut microbiome dysbiosis may be associated with select neuropsychological symptoms, although more research is needed to confirm this connection. This review will focus on the role of the gut microbiome and SIBO in IBS, as well as novel innovations that may help better characterize intestinal overgrowth and microbial dysbiosis.

Second Asian Consensus on Irritable Bowel Syndrome

BACKGROUND/AIMS

There has been major progress in our understanding of the irritable bowel syndrome (IBS), and novel treatment classes have emerged. The Rome IV guidelines were published in 2016 and together with the growing body of Asian data on IBS, we felt it is timely to update the Asian IBS Consensus.

METHODS

Key opinion leaders from Asian countries were organized into 4 teams to review 4 themes: symptoms and epidemiology, pathophysiology, diagnosis and investigations, and lifestyle modifications and treatments. The consensus development process was carried out by using a modified Delphi method.

RESULTS

Thirty-seven statements were developed. Asian data substantiate the current global viewpoint that IBS is a disorder of gut-brain interaction. Socio-cultural and environmental factors in Asia appear to influence the greater overlap between IBS and upper gastrointestinal symptoms. New classes of treatments comprising low fermentable oligo-, di-, monosacharides, and polyols diet, probiotics, non-absorbable antibiotics, and secretagogues have good evidence base for their efficacy.

CONCLUSIONS

Our consensus is that all patients with functional gastrointestinal disorders should be evaluated comprehensively with a view to holistic management. Physicians should be encouraged to take a positive attitude to the treatment outcomes for IBS patients.

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.

Association Between Small Intestinal Bacterial Overgrowth by Glucose Breath Test and Coronary Artery Disease

BACKGROUND

A possible role of gut bacteria and their metabolic by-products in the development of coronary artery disease (CAD) is suspected. There is a lack of studies evaluating the association of small intestinal bacterial overgrowth (SIBO) with the development of CAD.

AIM

To evaluate the frequency and risk factors for angiography-confirmed CAD in patients with or without SIBO.

METHODS

A total of 1059 patients tested for SIBO using the glucose hydrogen/methane breath test from 2006 to 2014 were evaluated. In total, 160 had coronary artery angiography and were included in the study. SIBO-positive patients were compared to SIBO-negative patients. Demographic, clinical, and laboratory variables and the presence of CAD on coronary angiography were analyzed.

RESULTS

Patients with SIBO had a higher frequency of CAD (78.9 vs. 38.6%, p < 0.001), diabetes mellitus (40.0 vs. 22.9%, p = 0.016), chronic kidney disease (26.7 vs. 12.9%, p = 0.025), use of angiotensin conversion enzyme inhibitor/blocker (45.5 vs. 32.9%, p = 0.008), and statins (75.6 vs. 61.4%, p = 0.004). Patients with SIBO had an increased number of coronary arteries affected compared to SIBO-negative patients (1-vessel disease 67.2 vs. 32.8%, p < 0.001; 2-vessel disease 85.7 vs. 14.3%, p < 0.001; and 3-vessel disease 82.4 vs. 17.6%, p < 0.001, respectively). In the stepwise multivariate logistic regression analysis, SIBO remained an independent risk factor for CAD (odds ratio 7.18, 95% confidence interval 3.09-16.67; p < 0.001).

CONCLUSION

SIBO was found to be associated with CAD and with the number of coronary arteries involved in this study from a single tertiary center. Further studies are necessary to confirm the association of SIBO with CAD. In the presence of risk factors, patients with SIBO may benefit from assessment for CAD.

Meta-analysis: proton pump inhibitors moderately increase the risk of small intestinal bacterial overgrowth

The use of proton pump inhibitors (PPIs) may potentially predispose to the development of small intestinal bacterial overgrowth (SIBO), but this association is controversial due to conflicting results from studies conducted to date. The aim of this meta-analysis was to evaluate the association between the use of PPIs and the risk of SIBO. We systematically searched the online PubMed, Embase, and Cochrane Library databases and Web of Science for relevant articles published up to November 2016. Two researchers identified and extracted data independent of each other. The pooled analysis was performed using the generic inverse-variance random-effects model. Subgroup and sensitivity analysis were conducted to assess the stability and heterogeneity of the pooled results. The risk of publication bias was evaluated by assessing for funnel plot asymmetry and by Egger's test and Begg's test. A total of 19 articles met the eligibility criteria for the meta-analysis, reporting on 7055 subjects. The pooled odds ratio (OR) showed a statistically significant association between increased risk of SIBO and PPI use (OR 1.71, 95% confidence interval 1.20-2.43). Subgroup analyses demonstrated an association between SIBO and PPI use in studies that employed small bowel aspirates culture and glucose hydrogen breath tests (GHBT) as diagnostic tests for SIBO. Our meta-analysis suggests that the use of PPI moderately increases the risk of SIBO, thereby highlighting the need for appropriate prescribing of PPIs.

Reduced interstitial cells of Cajal and increased intraepithelial lymphocytes are associated with development of small intestinal bacterial overgrowth in post-infectious IBS mouse model

OBJECTIVE

Intestinal dysmotility and immune activation are likely involved in the pathogenesis of small intestinal bacteria overgrowth (SIBO) in irritable bowel syndrome (IBS). We aimed at investigating the role of interstitial cells of Cajal (ICC) and intestinal inflammation in the development of SIBO using a post-infectious IBS (PI-IBS) mouse model.

MATERIALS AND METHODS

NIH mice were randomly infected with Trichinella spiralis. Visceral sensitivity and stool pattern were assessed at 8-weeks post-infection (PI). Intestinal bacteria counts from jejunum and ileum were measured by quantitative real-time PCR to evaluate the presence of SIBO. ICC density, intraepithelial lymphocytes (IELs) counts, and intestinal cytokine levels (IL1-β, IL-6, toll-like receptor-4 (TLR-4), IL-10) in the ileum were examined.

RESULTS

PI-IBS mice demonstrated increased visceral sensitivity compared with the control group. One-third of the PI-IBS mice developed SIBO (SIBO+/PI-IBS) and was more likely to have abnormal stool form compared with SIBO negative PI-IBS (SIBO-/PI-IBS) mice but without difference in visceral sensitivity. SIBO+/PI-IBS mice had decreased ICC density and increased IELs counts in the ileum compared with SIBO-/PI-IBS mice. No difference in inflammatory cytokine expression levels were detected among the groups except for increased TLR-4 in PI-IBS mice compared with the control group.

CONCLUSIONS

Development of SIBO in PI-IBS mice was associated with reduced ICC density and increased IELs counts in the ileum. Our findings support the role of intestinal dysmotility and inflammation in the pathogenesis of SIBO in IBS and may provide potential therapeutic targets.

Small intestinal bacterial overgrowth as a cause for irritable bowel syndrome: guilty or not guilty?

PURPOSE OF REVIEW

Small intestinal bacterial overgrowth (SIBO) has been proposed as a cause of irritable bowel syndrome (IBS). However, this relationship has been subject to controversy. This review aims to provide a current perspective on the SIBO-IBS hypothesis.

RECENT FINDINGS

Case-control studies evaluating the prevalence of SIBO in IBS and healthy individuals have shown conflicting results. Moreover, the tests available in routine clinical practice to diagnose SIBO are not valid and lack both sensitivity and specificity. Hence, interpreting the effect of interventions based on these tests is fraught with uncertainty. Furthermore, the SIBO-IBS hypothesis has paved the way to assess antibiotic therapy in nonconstipated IBS, with rifaximin, a nonabsorbable antibiotic, showing modest but significant clinical benefit. However, individuals were not tested for SIBO and the mechanism of action of rifaximin in IBS remains to be elucidated. Preliminary data suggest that rifaximin decreases microbial richness and previous studies have noted antibacterial interventions in IBS to reduce colonic fermentation and improve symptoms. The advent of rapid culture-independent molecular techniques is a promising tool that will seek to clarify and advance our understanding of the gut microbial function.

SUMMARY

The SIBO-IBS hypothesis lacks convincing evidence but remains under scrutiny. The mechanism resulting in symptom improvement after rifaximin treatment in some IBS individuals requires exploration. Novel molecular techniques provide an exciting and challenging opportunity to explore the host-gut microbiota interaction.

Applications of Fuzi Lizhong decoction in digestive system diseases

Fuzi Lizhong decoction came from "Treatise on Three Categories of Pathogenic Factors", and it can nourish the spleen and stomach and treat middle Jiao deficiency or Yang deficiency of the spleen and kidney. Although Fuzi Lizhong decoction is famous for warming middle Jiao to dispel cold, it was rarely used alone to treat digestive system diseases. Modern physicians often combine Fuzi Lizhong decoction with traditional Chinese medicine or Western medicine to treat digestive system diseases, such as irritable bowel syndrome, drug-induced liver injury, chronic gastritis, ulcerative colitis, functional dyspepsia, chronic diarrhea and so on, with significant effects observed. This reflects the philosophy of treatment based on syndrome differentiation and same treatment for different diseases for traditional Chinese medicine. We recommend that in future research and clinical applications, Fuzi Lizhong decoction should be combined with emotional therapy based on the experience of traditional Chinese medicine to better exploit the unique advantages of traditional Chinese medicine in the treatment of digestive diseases.

Live combined Bacillus subtilis and Enterococcus faecium granules combined with rifaximin for treatment of small intestinal bacterial overgrowth

AIM

To evaluate the efficacy of live combined Bacillus subtilis and Enterococcus faecium granules combined with rifaximin in the treatment of small intestinal bacterial overgrowth (SIBO) in patients with diarrhea-type irritable bowel syndrome (IBS).

METHODS

From April 2015 to April 2016, 84 IBS patients with SIBO treated at the First Affiliated Hospital of Zhengzhou University were included. The patients were randomly divided into either a treatment group (n = 41) or a control group (n = 43). The treatment group received live combined Bacillus subtilis and Enterococcus faecium granules combined with rifaximin for 14 d, while the control group received rifaximin alone. After treatment, the curative effect was compared between the two groups.

RESULTS

The rate of conversion from positive to negative SIBO was significantly higher in the treatment group than in the control group (85.37% vs 60.47%, P < 0.05). There was also a statistically significant difference in the treatment efficiency between the treatment group and control group (92.69% vs 62.76%, P < 0.01).

CONCLUSION

The efficacy of rifaximin combined with live combined Bacillus subtilis and Enterococcus faecium granules is significant in IBS patients with SIBO.