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Shah A, Fairlie T, Morrison M, Martin N, Hammer K, Hammer J, Koloski N, Rezaie A, Pimentel M, Kashyap P, Jones MP, Holtmann G. Prevalence of small intestinal bacterial overgrowth in intestinal failure syndrome: A systematic review and meta-analysis. J Gastroenterol Hepatol 2024. [PMID: 38934370 DOI: 10.1111/jgh.16668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 06/01/2024] [Accepted: 06/12/2024] [Indexed: 06/28/2024]
Abstract
BACKGROUND AND AIM Patients with intestinal failure (IF) have abnormal intestinal anatomy, secretion, and dysmotility, which impairs intestinal homeostatic mechanisms and may lead to small intestinal bacterial overgrowth (SIBO). We conducted a systematic review and meta-analysis to determine the prevalence of SIBO in patients with IF and to identify risk factors for SIBO. METHODS MEDLINE (PubMed) and Embase electronic databases were searched from inception to December 2023 for studies that reported the prevalence of SIBO in IF. The prevalence rates, odds ratio (OR), and 95% confidence intervals of SIBO in IF and the risk factors for SIBO in IF were calculated using random effects model. RESULTS Final dataset included nine studies reporting on 407 patients with IF. The prevalence of SIBO in IF was 57.5% (95% CI 44.6-69.4), with substantial heterogeneity in this analysis (I2 = 80.9, P = 0.0001). SIBO prevalence was sixfold higher in patients with IF who received parenteral nutrition (PN) compared with IF patients not on PN (OR = 6.0, 95% CI 3.0-11.9, P = 0.0001). Overall, the prevalence of SIBO in patients with IF using PPI/acid-suppressing agents (72.0%, 95% CI 57.5-83.8) was numerically higher compared with IF patients not using these agents (47.6%, 95% CI 25.7-70.2). CONCLUSIONS This systematic review and meta-analysis suggests that there is an increased risk of SIBO in patients with IF and that PN, and potentially, the use of PPI/acid-suppressing agents is risk factors for SIBO development in patients with IF. However, the quality of evidence is low and can be attributed to lack of case-control studies and clinical heterogeneity seen in the studies.
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Affiliation(s)
- Ayesha Shah
- Faculty of Medicine, University of Queensland, Brisbane, Queensland, Australia
- Department of Gastroenterology and Hepatology, Princess Alexandra Hospital, Brisbane, Queensland, Australia
- Translational Research Institute, Brisbane, Queensland, Australia
| | - Thomas Fairlie
- Faculty of Medicine, University of Queensland, Brisbane, Queensland, Australia
- Department of Gastroenterology and Hepatology, Princess Alexandra Hospital, Brisbane, Queensland, Australia
- Translational Research Institute, Brisbane, Queensland, Australia
| | - Mark Morrison
- Faculty of Medicine, University of Queensland, Brisbane, Queensland, Australia
- Department of Gastroenterology and Hepatology, Princess Alexandra Hospital, Brisbane, Queensland, Australia
- Faculty of Medicine, Frazer Institute, University of Queensland, Woolloongabba, Queensland, Australia
| | - Neal Martin
- Faculty of Medicine, University of Queensland, Brisbane, Queensland, Australia
- Department of Gastroenterology and Hepatology, Princess Alexandra Hospital, Brisbane, Queensland, Australia
| | - Karin Hammer
- St. Anna Kinderspital, Medical University of Vienna, Vienna, Austria
| | - Johann Hammer
- Department of Gastroenterology and Hepatology, Medical University of Vienna, Vienna, Austria
| | - Natasha Koloski
- Faculty of Medicine, University of Queensland, Brisbane, Queensland, Australia
- Department of Gastroenterology and Hepatology, Princess Alexandra Hospital, Brisbane, Queensland, Australia
- Translational Research Institute, Brisbane, Queensland, Australia
| | - Ali Rezaie
- Karsh Division of Gastroenterology and Hepatology, Department of Medicine, Medically Associated Science and Technology (MAST) Program, Cedars-Sinai, Los Angeles, California, USA
| | - Mark Pimentel
- Karsh Division of Gastroenterology and Hepatology, Department of Medicine, Medically Associated Science and Technology (MAST) Program, Cedars-Sinai, Los Angeles, California, USA
| | - Purna Kashyap
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota, USA
| | - Michael P Jones
- School of Psychological Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Gerald Holtmann
- Faculty of Medicine, University of Queensland, Brisbane, Queensland, Australia
- Department of Gastroenterology and Hepatology, Princess Alexandra Hospital, Brisbane, Queensland, Australia
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Shah A, Ghoshal UC, Holtmann GJ. Unravelling the controversy with small intestinal bacterial overgrowth. Curr Opin Gastroenterol 2023; 39:211-218. [PMID: 37144539 DOI: 10.1097/mog.0000000000000928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
PURPOSE OF REVIEW The aim of this review is to summarize the current and emergent approaches to characterize the small intestinal microbiota and discuss the treatment options for management of small intestinal bacterial overgrowth (SIBO). RECENT FINDINGS This review captures the growing body of evidence for the role of SIBO, a type of small intestinal dysbiosis in the pathophysiology various gastrointestinal and extraintestinal disorders. We have highlighted the drawbacks of the available methods for characterizing the small intestinal microbiota and focus on the new culture-independent techniques to diagnose SIBO. Although recurrence is common, targeted modulation of the gut microbiome as a therapeutic option for management of SIBO is associated with improvement in symptoms and quality of life. SUMMARY As a first step to precisely characterize the potential link between SIBO and various disorders, we need to address the methodological limitations of the available traditional tests for diagnosing SIBO. There is an urgency to develop culture independent techniques that can be routinely used in clinical setting, that will enable characterization of the gastrointestinal microbiome and explore the response to antimicrobial therapy including the links between long-lasting symptom resolution and the microbiome.
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Affiliation(s)
- Ayesha Shah
- The University of Queensland, Faculty of Medicine and Faculty of Health and Behavioural Sciences
- Princess Alexandra Hospital, Department of Gastroenterology & Hepatology, Brisbane, QLD, Australia
| | - Uday C Ghoshal
- Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India
| | - Gerald J Holtmann
- The University of Queensland, Faculty of Medicine and Faculty of Health and Behavioural Sciences
- Princess Alexandra Hospital, Department of Gastroenterology & Hepatology, Brisbane, QLD, Australia
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Mandarino FV, Sinagra E, Raimondo D, Danese S. The Role of Microbiota in Upper and Lower Gastrointestinal Functional Disorders. Microorganisms 2023; 11:microorganisms11040980. [PMID: 37110403 PMCID: PMC10144014 DOI: 10.3390/microorganisms11040980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 04/04/2023] [Accepted: 04/06/2023] [Indexed: 04/29/2023] Open
Abstract
Functional gastrointestinal disorders (FGIDs), also known as disorders of gut-brain interaction, are a group of disorders characterized by chronic gastrointestinal symptoms in the absence of demonstrable pathology on conventional testing [...].
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Affiliation(s)
- Francesco Vito Mandarino
- Division of Gastroenterology and Gastrointestinal Endoscopy, San Raffaele Hospital, 20132 Milan, Italy
| | - Emanuele Sinagra
- Gastroenterology & Endoscopy Unit, Fondazione Istituto G. Giglio, Contrada Pietra Pollastra Pisciotto, 90015 Cefalù, Italy
| | - Dario Raimondo
- Gastroenterology & Endoscopy Unit, Fondazione Istituto G. Giglio, Contrada Pietra Pollastra Pisciotto, 90015 Cefalù, Italy
| | - Silvio Danese
- Division of Gastroenterology and Gastrointestinal Endoscopy, San Raffaele Hospital, 20132 Milan, Italy
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Shah A, Kang S, Talley NJ, Do A, Walker MM, Shanahan ER, Koloski NA, Jones MP, Keely S, Morrison M, Holtmann GJ. The duodenal mucosa associated microbiome, visceral sensory function, immune activation and psychological comorbidities in functional gastrointestinal disorders with and without self-reported non-celiac wheat sensitivity. Gut Microbes 2022; 14:2132078. [PMID: 36303431 PMCID: PMC9621048 DOI: 10.1080/19490976.2022.2132078] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Frequently, patients with functional gastrointestinal disorders (FGIDs) report intolerance of wheat products. We compared gastrointestinal symptoms, sensory function, psychiatric comorbidities, gut-homing immune cells, and duodenal mucosa-associated microbiome (d-MAM) in FGID patients and controls with and without self-reported wheat sensitivity (SR-NCWS). We recruited 40 FGID patients and 20 controls referred by GPs for treatment. Gastrointestinal/extraintestinal symptoms, visceral sensory function, psychological comorbidities, and SR-NCWS were assessed in a standardized approach. Peripheral gut homing T-cells (CD4+α4+β7+CCR9+/CD8+α4+β7+CCR9+) were quantified, and the d-MAM was assessed by DNA sequencing for 46 subjects. Factors of bacterial genera were extracted utilizing factor analysis with varimax rotation and factors univariately associated with FGID or SR-NCWS included in a subsequent multivariate analysis of variance to identify statistically independent discriminators. Anxiety scores (p < .05) and increased symptom responses to a nutrient challenge (p < .05) were univariately associated with FGID. Gut homing T-cells were increased in FGID patients with SR-NCWS compared to other groups (p all <0.05). MANOVA revealed that anxiety (p = .03), visceral sensory function (p = 0.007), and a d-MAM factor comprise members of the Alloprevotella, Prevotella, Peptostreptococcus, Leptotrichia, and Veillonella lineages were significantly (p = .001) associated with FGID, while gut homing CD4+α4+ β7+CCR9+ T-cells were associated (p = .002) with SR-NCWS. Compared to controls, patients with and without SR-NCWS show that there are shifts in the amplicon sequence variants within specific bacterial genera between the FGID subgroups (particularly Prevotella and Streptococcus) as well as distinct bacterial taxa discriminatory for the two different FGID subtypes. Compared to controls, both FGID patients with and without SR-NCWS have an increased symptom response to a standardized nutrient challenge and increased anxiety scores. The FGID patients with SR-NCWS - as compared to FGID without SR-NCWS (and controls without SR-NCWS) - have increased gut homing T-cells. The d-MAM profiles suggest species and strain-based variations between the two FGID subtypes and in comparison to controls.
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Affiliation(s)
- Ayesha Shah
- Department of Gastroenterology and Hepatology, Princess Alexandra Hospital, Brisbane, Australia,Translational Research Institute Queensland, Australia,Faculty of Medicine, University of Queensland, Brisbane, Australia
| | - Seungha Kang
- Faculty of Medicine, University of Queensland, Brisbane, Australia,University of Queensland Diamantina Institute, Woolloongabba, Australia
| | - Nicholas J Talley
- College of Health, Medicine and Wellbeing, University of Newcastle, Callaghan, and Hunter Medical Research Institute, New Lambton Heights, Australia
| | - Anh Do
- Department of Gastroenterology and Hepatology, Princess Alexandra Hospital, Brisbane, Australia,Faculty of Medicine, University of Queensland, Brisbane, Australia
| | - Marjorie M Walker
- College of Health, Medicine and Wellbeing, University of Newcastle, Callaghan, and Hunter Medical Research Institute, New Lambton Heights, Australia
| | - Erin R Shanahan
- Department of Gastroenterology and Hepatology, Princess Alexandra Hospital, Brisbane, Australia,Translational Research Institute Queensland, Australia
| | - Natasha A Koloski
- Department of Gastroenterology and Hepatology, Princess Alexandra Hospital, Brisbane, Australia,Translational Research Institute Queensland, Australia,Faculty of Medicine, University of Queensland, Brisbane, Australia,College of Health, Medicine and Wellbeing, University of Newcastle, Callaghan, and Hunter Medical Research Institute, New Lambton Heights, Australia
| | - Michael P Jones
- College of Health, Medicine and Wellbeing, University of Newcastle, Callaghan, and Hunter Medical Research Institute, New Lambton Heights, Australia
| | - Simon Keely
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, and Hunter Medical Research Institute, New Lambton Heights, Australia
| | - Mark Morrison
- Department of Gastroenterology and Hepatology, Princess Alexandra Hospital, Brisbane, Australia,Faculty of Medicine, University of Queensland, Brisbane, Australia,University of Queensland Diamantina Institute, Woolloongabba, Australia,CONTACT Mark Morrison
| | - Gerald J Holtmann
- Department of Gastroenterology and Hepatology, Princess Alexandra Hospital, Brisbane, Australia,Translational Research Institute Queensland, Australia,Faculty of Medicine, University of Queensland, Brisbane, Australia,Gerald J Holtmann Princess Alexandra Hospital, Brisbane Department of Gastroenterology and Hepatology & University of Queensland 199 Ipswich Road, Woolloongabba, Queensland, Australia
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Shah A, Thite P, Hansen T, Kendall BJ, Sanders DS, Morrison M, Jones MP, Holtmann G. Links between celiac disease and small intestinal bacterial overgrowth: A systematic review and meta-analysis. J Gastroenterol Hepatol 2022; 37:1844-1852. [PMID: 35734803 PMCID: PMC9795979 DOI: 10.1111/jgh.15920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 06/19/2022] [Indexed: 12/30/2022]
Abstract
BACKGROUND AND AIM Symptoms of small intestinal bacterial overgrowth (SIBO) and celiac disease (CeD) often overlap, and studies suggest a link between SIBO and CeD. We thus conducted a systematic review and meta-analysis to compare SIBO prevalence in CeD patients and controls and assessed effects of antimicrobial therapy on gastrointestinal symptoms in SIBO positive CeD patients. METHODS Electronic databases were searched until February 2022 for studies reporting SIBO prevalence in CeD. Prevalence rates, odds ratio (OR), and 95% confidence intervals (CI) of SIBO in CeD and controls were calculated. RESULTS We included 14 studies, with 742 CeD patients and 178 controls. The pooled prevalence of SIBO in CeD was 18.3% (95% CI: 11.4-28.1), with substantial heterogeneity. Including case-control studies with healthy controls, SIBO prevalence in CeD patients was significantly increased (OR 5.1, 95% CI: 2.1-12.4, P = 0.0001), with minimal heterogeneity. Utilizing breath tests, SIBO prevalence in CeD patients was 20.8% (95% CI: 11.9-33.7), almost two-fold higher compared with culture-based methods at 12.6% (95% CI: 5.1-28.0), with substantial heterogeneity in both analyses. SIBO prevalence in CeD patients nonresponsive to a gluten free diet (GFD) was not statistically higher as compared with those responsive to GFD (OR 1.5, 95% CI: 0.4-5.0, P = 0.511). Antibiotic therapy of SIBO positive CeD patients resulted in improvement in gastrointestinal symptoms in 95.6% (95% CI: 78.0-99.9) and normalization of breath tests. CONCLUSIONS This study suggests a link between SIBO and CeD. While SIBO could explain nonresponse to a GFD in CeD, SIBO prevalence is not statistically higher in CeD patients non-responsive to GFD. The overall quality of the evidence is low, mainly due to substantial "clinical heterogeneity" and the limited sensitivity/specificity of the available diagnostic tests.
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Affiliation(s)
- Ayesha Shah
- Faculty of MedicineThe University of QueenslandBrisbaneQueenslandAustralia,Department of Gastroenterology and HepatologyPrincess Alexandra HospitalWoolloongabbaQueenslandAustralia,Translational Research InstituteWoolloongabbaQueenslandAustralia
| | - Parag Thite
- Faculty of MedicineThe University of QueenslandBrisbaneQueenslandAustralia,Department of Gastroenterology and HepatologyPrincess Alexandra HospitalWoolloongabbaQueenslandAustralia
| | - Teressa Hansen
- Faculty of MedicineThe University of QueenslandBrisbaneQueenslandAustralia,Department of Gastroenterology and HepatologyPrincess Alexandra HospitalWoolloongabbaQueenslandAustralia,Translational Research InstituteWoolloongabbaQueenslandAustralia
| | - Bradley J Kendall
- Faculty of MedicineThe University of QueenslandBrisbaneQueenslandAustralia,Department of Gastroenterology and HepatologyPrincess Alexandra HospitalWoolloongabbaQueenslandAustralia
| | - David S Sanders
- Academic Unit of GastroenterologySheffield Teaching Hospitals NHS Foundation TrustSheffieldUK
| | - Mark Morrison
- Faculty of MedicineThe University of QueenslandBrisbaneQueenslandAustralia,Department of Gastroenterology and HepatologyPrincess Alexandra HospitalWoolloongabbaQueenslandAustralia,Diamantina InstituteThe University of QueenslandBrisbaneQueenslandAustralia
| | - Michael P Jones
- Department of PsychologyMacquarie UniversitySydneyNew South WalesAustralia
| | - Gerald Holtmann
- Faculty of MedicineThe University of QueenslandBrisbaneQueenslandAustralia,Department of Gastroenterology and HepatologyPrincess Alexandra HospitalWoolloongabbaQueenslandAustralia,Translational Research InstituteWoolloongabbaQueenslandAustralia
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Evidence-Based and Emerging Diet Recommendations for Small Bowel Disorders. Am J Gastroenterol 2022; 117:958-964. [PMID: 35404303 PMCID: PMC9169759 DOI: 10.14309/ajg.0000000000001764] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 04/01/2022] [Indexed: 02/06/2023]
Abstract
Diet plays a key role in the manifestation and severity of gastrointestinal symptoms, with increasing research interest on the role of diet in small bowel disorders. There are predominantly 3 small bowel conditions that have potential dietary interventions. Self-reported nonceliac gluten/wheat sensitivity is prevalent. Although gluten is believed to be a potential trigger for symptoms, other components of wheat may also be triggers, including fructans, alpha-amylase trypsin inhibitors, and wheat germ agglutinins. The diagnosis can be challenging, given the lack of validated biomarkers. A gluten-free diet that excludes the abovementioned triggers is the cornerstone of treatment; however, unlike celiac disease, there is uncertainty about the level of adherence or whether the gluten-free diet is a lifelong intervention. Several primary gastrointestinal disorders are associated with an increase in inflammatory cells including eosinophils. Diet seems to be an important driver of disease pathogenesis in eosinophilic gastroenteritis, with elimination and elemental diets showing promise in management, with further robust trials required. Small intestinal bacterial overgrowth is an example of microbial dysbiosis, with renewed interest in diet being postulated to cause an adaptive change of the microbes colonizing the small intestine. However, the diagnosis of small intestinal bacterial overgrowth is limited by a lack of sensitive and specific tests, with significant knowledge gaps in relation to therapeutic measures to manage and cure small intestinal bacterial overgrowth. Currently, antimicrobials are the established management option. There have been significant clinical advances in dietary interventions related to the small bowel, but this area is currently a novel and advancing field for both patients and clinicians.
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Concomitant Irritable Bowel Syndrome Does Not Influence the Response to Antimicrobial Therapy in Patients with Functional Dyspepsia. Dig Dis Sci 2022; 67:2299-2309. [PMID: 34392491 DOI: 10.1007/s10620-021-07149-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 05/03/2021] [Indexed: 12/12/2022]
Abstract
BACKGROUND AND AIMS Antimicrobial therapy improves symptoms in patients with irritable bowel syndrome (IBS), but the efficacy in functional dyspepsia (FD) is largely unknown. While FD and IBS frequently overlap, it is unknown if concomitant IBS in FD alters the response to antimicrobial therapy in FD. Thus, we aimed to assess and compare the effect of antimicrobial therapy on visceral sensory function and symptom improvement in FD patients with and without IBS. METHODS Adult patients with FD with or without IBS received rifaximin 550 mg BD for 10 days, followed by a 6-week follow-up period. The total gastrointestinal symptom score as measured by the SAGIS (Structured Assessment of Gastrointestinal Symptoms) questionnaire and subscores (dyspepsia, diarrhea, and constipation), symptom response to a standardized nutrient challenge and normalization of the glucose breath tests were measured. RESULTS Twenty-one consecutive adult patients with FD and 14/21 with concomitant IBS were recruited. Treatment with rifaximin resulted in a significant (p = 0.017) improvement in the total SAGIS score from 34.7 (± 15.4) at baseline to 26.0 (± 16.8) at 2 weeks and 25.6 (± 17.8) at 6 weeks post-treatment. Similarly, compared to baseline there was a statistically significant improvement in SAGIS subscores for dyspepsia and diarrhea (all p < 0.05) and effects persisted for 6 weeks post-treatment. Similarly, the symptom score (and subscores) following a standardized nutrient challenge improved significantly (p < 0.001) 2 weeks post-treatment. The presence of concomitant IBS did not significantly influence the improvement of symptoms after antibiotic therapy (all p > 0.5). CONCLUSIONS In FD patients, the response to antimicrobial therapy with rifaximin is not influenced by concomitant IBS symptoms.
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Shah A, Talley NJ, Holtmann G. Current and Future Approaches for Diagnosing Small Intestinal Dysbiosis in Patients With Symptoms of Functional Dyspepsia. Front Neurosci 2022; 16:830356. [PMID: 35600619 PMCID: PMC9121133 DOI: 10.3389/fnins.2022.830356] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 03/28/2022] [Indexed: 12/12/2022] Open
Abstract
The development and application of next generation sequencing technologies for clinical gastroenterology research has provided evidence that microbial dysbiosis is of relevance for the pathogenesis of gastrointestinal and extra-intestinal diseases. Microbial dysbiosis is characterized as alterations of diversity, function, and density of the intestinal microbes. Emerging evidence suggests that alterations of the gastrointestinal microbiome are important for the pathophysiology of a variety of functional gastrointestinal conditions, e.g., irritable bowel syndrome (IBS) and functional dyspepsia (FD), also known as disorders of brain-gut axis interaction. Clinicians have for many years recognized that small intestinal bacterial overgrowth (SIBO) is typified by a microbial dysbiosis that is underpinned by abnormal bacterial loads in these sites. SIBO presents with symptoms which overlap with symptoms of FD and IBS, point toward the possibility that SIBO is either the cause or the consequence of functional gastrointestinal disorders (FGIDs). More recently, new terms including "intestinal methanogen overgrowth" and "small intestinal fungal overgrowth" have been introduced to emphasize the contribution of methane production by archea and fungi in small intestinal dysbiosis. There is emerging data that targeted antimicrobial treatment of SIBO in patients with FD who simultaneously may or may not have IBS, results in symptom improvement and normalization of positive breath tests. However, the association between SIBO and FGIDs remains controversial, since widely accepted diagnostic tests for SIBO are lacking. Culture of jejunal fluid aspirate has been proposed as the "traditional gold standard" for establishing the diagnosis of SIBO. Utilizing jejunal fluid culture, the results can potentially be affected by cross contamination from oropharyngeal and luminal microbes, and there is controversy regarding the best cut off values for SIBO diagnosis. Thus, it is rarely used in routine clinical settings. These limitations have led to the development of breath tests, which when compared with the "traditional gold standard," have sub-optimal sensitivity and specificity for SIBO diagnosis. With newer diagnostic approaches-based upon applications of the molecular techniques there is an opportunity to characterize the duodenal and colonic mucosa associated microbiome and associated gut microbiota dysbiosis in patients with various gastrointestinal and extraintestinal diseases. Furthermore, the role of confounders like psychological co-morbidities, medications, dietary practices, and environmental factors on the gastrointestinal microbiome in health and disease also needs to be explored.
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Affiliation(s)
- Ayesha Shah
- Faculty of Medicine and Faculty of Health and Behavioural Sciences, The University of Queensland, Brisbane, QLD, Australia
- Department of Gastroenterology and Hepatology, Princess Alexandra Hospital, Brisbane, QLD, Australia
- AGIRA (Australian Gastrointestinal Research Alliance) and the NHMRC Centre of Research Excellence in Digestive Health, Newcastle, NSW, Australia
| | - Nicholas J. Talley
- AGIRA (Australian Gastrointestinal Research Alliance) and the NHMRC Centre of Research Excellence in Digestive Health, Newcastle, NSW, Australia
- College of Health, Medicine and Wellbeing, University of Newcastle, Callaghan, NSW, Australia
| | - Gerald Holtmann
- Faculty of Medicine and Faculty of Health and Behavioural Sciences, The University of Queensland, Brisbane, QLD, Australia
- Department of Gastroenterology and Hepatology, Princess Alexandra Hospital, Brisbane, QLD, Australia
- AGIRA (Australian Gastrointestinal Research Alliance) and the NHMRC Centre of Research Excellence in Digestive Health, Newcastle, NSW, Australia
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Burns GL, Talley NJ, Keely S. Immune responses in the irritable bowel syndromes: time to consider the small intestine. BMC Med 2022; 20:115. [PMID: 35354471 PMCID: PMC8969236 DOI: 10.1186/s12916-022-02301-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 02/15/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Irritable bowel syndrome (IBS) is considered a disorder of gut-brain interaction (DGBI), presenting as chronic abdominal pain and altered defaecation. Symptoms are often food related. Much work in the field has focused on identifying physiological, immune and microbial abnormalities in the colon of patients; however, evidence of small intestinal immune activation and microbial imbalance has been reported in small studies. The significance of such findings has been largely underappreciated despite a growing body of work implicating small intestinal homeostatic imbalance in the pathogenesis of DGBIs. MAIN TEXT Small intestinal mechanosensation is a characteristic feature of IBS. Furthermore, altered small intestinal barrier functions have been demonstrated in IBS patients with the diarrhoea-predominant subtype. Small intestinal bacterial overgrowth and increased populations of small intestinal mast cells are frequently associated with IBS, implicating microbial imbalance and low-grade inflammation in the pathogenesis of IBS. Furthermore, reports of localised food hypersensitivity responses in IBS patients implicate the small intestine as the site of immune-microbial-food interactions. CONCLUSIONS Given the association of IBS symptoms with food intake in a large proportion of patients and the emerging evidence of immune activation in these patients, the current literature suggests the pathogenesis of IBS is not limited to the colon but rather may involve dysfunction of the entire intestinal tract. It remains unclear if regional variation in IBS pathology explains the various symptom phenotypes and further work should consider the intestinal tract as a whole to answer this question.
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Affiliation(s)
- Grace L Burns
- NHMRC Centre of Research Excellence in Digestive Health, The University of Newcastle, Callaghan, New South Wales, Australia.,College of Health, Medicine and Wellbeing, The University of Newcastle, Callaghan, New South Wales, Australia.,Immune Health Program, Hunter Medical Research Institute, New Lambton Heights, New South Wales, Australia
| | - Nicholas J Talley
- NHMRC Centre of Research Excellence in Digestive Health, The University of Newcastle, Callaghan, New South Wales, Australia.,College of Health, Medicine and Wellbeing, The University of Newcastle, Callaghan, New South Wales, Australia.,Immune Health Program, Hunter Medical Research Institute, New Lambton Heights, New South Wales, Australia
| | - Simon Keely
- NHMRC Centre of Research Excellence in Digestive Health, The University of Newcastle, Callaghan, New South Wales, Australia. .,College of Health, Medicine and Wellbeing, The University of Newcastle, Callaghan, New South Wales, Australia. .,Immune Health Program, Hunter Medical Research Institute, New Lambton Heights, New South Wales, Australia.
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Shah A, Holtmann G. Small intestinal bacterial overgrowth in inflammatory bowel disease. Indian J Gastroenterol 2022; 41:23-29. [PMID: 35031976 DOI: 10.1007/s12664-021-01235-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 12/06/2021] [Indexed: 02/04/2023]
Affiliation(s)
- Ayesha Shah
- Faculty of Medicine and Faculty of Health and Behavioral Sciences, The University of Queensland, Brisbane, Australia. .,Department of Gastroenterology and Hepatology, Princess Alexandra Hospital, Brisbane, Australia. .,AGIRA (Australian Gastrointestinal Research Alliance) and the NHMRC Centre of Research Excellence in Digestive Health, Brisbane, Australia.
| | - Gerald Holtmann
- Faculty of Medicine and Faculty of Health and Behavioral Sciences, The University of Queensland, Brisbane, Australia.,Department of Gastroenterology and Hepatology, Princess Alexandra Hospital, Brisbane, Australia.,AGIRA (Australian Gastrointestinal Research Alliance) and the NHMRC Centre of Research Excellence in Digestive Health, Brisbane, Australia
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Gandhi A, Shah A, Jones MP, Koloski N, Talley NJ, Morrison M, Holtmann G. Methane positive small intestinal bacterial overgrowth in inflammatory bowel disease and irritable bowel syndrome: A systematic review and meta-analysis. Gut Microbes 2022; 13:1933313. [PMID: 34190027 PMCID: PMC8253120 DOI: 10.1080/19490976.2021.1933313] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Several studies reported a potential role of methane producing archaea in the pathophysiology of irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). We conducted a systematic review and meta-analysis to assess the prevalence of methane positive small intestinal bacterial overgrowth (SIBO) in IBS and IBD compared with controls. MEDLINE (PubMed) and Embase electronic databases were searched from inception until March 2021 for case-control and prevalence studies reporting SIBO in IBS and IBD. We extracted data from published studies and calculated pooled prevalence of SIBO in IBS or IBD, odds ratios (OR), and 95% CIs, utilizing a random effects model. The final dataset included 17 independent studies assessing the prevalence of methane positive SIBO in 1,653 IBS-patients and 713 controls, and 7 studies assessing the prevalence of methane positive SIBO in 626 IBD-patients and 497 controls, all utilizing breath test for SIBO diagnosis. Prevalence of methane positive SIBO in IBS and IBD was 25.0% (95% CI 18.8-32.4) and 5.6% (95% CI 2.6-11.8), respectively. Methane positive SIBO in IBS was not increased compared to controls (OR = 1.2, 95% CI 0.8-1.7, P = .37) but was significantly more prevalent in IBS-C as compared to IBS-D (OR = 3.1, 95% CI 1.7-5.6, P = .0001). The prevalence of methane-positive SIBO in patients with IBD was 3-fold lower at 7.4% (95% CI 5.4-9.8) compared to 23.5% (95% CI 19.8-27.5) in controls. The prevalence of methane positive SIBO was significantly lower in Crohn's disease as compared to ulcerative colitis, (5.3%, 95% CI 3.0-8.5 vs. 20.2%, 95% CI 12.8-29.4). This systematic review and meta-analysis suggests methane positivity on breath testing is positively associated with IBS-C and inversely with IBD. However, the quality of evidence is low largely due to clinical heterogeneity of the studies. Thus, causality is uncertain and further studies are required.
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Affiliation(s)
- Arjun Gandhi
- Faculty of Medicine, The University of Queensland, Queensland, Australia,Department of Gastroenterology & Hepatology, Princess Alexandra Hospital, Brisbane, Queensland, Australia
| | - Ayesha Shah
- Faculty of Medicine, The University of Queensland, Queensland, Australia,Department of Gastroenterology & Hepatology, Princess Alexandra Hospital, Brisbane, Queensland, Australia,Translational Research Institute, Brisbane, Queensland, Australia
| | - Michael P. Jones
- Department of Psychology, Macquarie University, Sydney, New South Wales, Australia
| | - Natasha Koloski
- Faculty of Medicine, The University of Queensland, Queensland, Australia,Department of Gastroenterology & Hepatology, Princess Alexandra Hospital, Brisbane, Queensland, Australia,Translational Research Institute, Brisbane, Queensland, Australia
| | - Nicholas J. Talley
- Faculty of Health and Medicine, The University of Newcastle, Newcastle, Australia
| | - Mark Morrison
- Faculty of Medicine, The University of Queensland, Queensland, Australia,Department of Gastroenterology & Hepatology, Princess Alexandra Hospital, Brisbane, Queensland, Australia,University of Queensland, Diamantina Institute, Brisbane, Queensland, Australia
| | - Gerald Holtmann
- Faculty of Medicine, The University of Queensland, Queensland, Australia,Department of Gastroenterology & Hepatology, Princess Alexandra Hospital, Brisbane, Queensland, Australia,Translational Research Institute, Brisbane, Queensland, Australia,CONTACT Gerald Holtmann Brisbane Department of Gastroenterology and Hepatology & University of Queensland Ipswich Road, Woolloongabba, Queensland, Australia
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12
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Ghoshal UC, Sachdeva S, Ghoshal U, Misra A, Puri AS, Pratap N, Shah A, Rahman MM, Gwee KA, Tan VPY, Ahmed T, Lee YY, Ramakrishna BS, Talukdar R, Rana SV, Sinha SK, Chen M, Kim N, Holtmann G. Asian-Pacific consensus on small intestinal bacterial overgrowth in gastrointestinal disorders: An initiative of the Indian Neurogastroenterology and Motility Association. Indian J Gastroenterol 2022; 41:483-507. [PMID: 36214973 PMCID: PMC9549446 DOI: 10.1007/s12664-022-01292-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 08/02/2022] [Indexed: 02/04/2023]
Abstract
In the clinical setting, small intestinal bacterial overgrowth (SIBO) is a frequent, but under-diagnosed entity. SIBO is linked to various gastrointestinal (GI) and non-GI disorders with potentially significant morbidity. The optimal management of SIBO is undefined while there is a lack of published consensus guidelines. Against this background, under the auspices of the Indian Neurogastroenterology and Motility Association (INMA), formerly known as the Indian Motility and Functional Diseases Association (IMFDA), experts from the Asian-Pacific region with extensive research and clinical experience in the field of gut dysbiosis including SIBO developed this evidence-based practice guideline for the management of SIBO utilizing a modified Delphi process based upon 37 consensus statements, involving an electronic voting process as well as face-to-face meetings and review of relevant supporting literature. These statements include 6 statements on definition and epidemiology; 11 on etiopathogenesis and pathophysiology; 5 on clinical manifestations, differential diagnosis, and predictors; and 15 on investigations and treatment. When the proportion of those who voted either to accept completely or with minor reservations was 80% or higher, the statement was regarded as accepted. The members of the consensus team consider that this guideline would be valuable to inform clinical practice, teaching, and research on SIBO in the Asian-Pacific region as well as in other countries.
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Affiliation(s)
- Uday C. Ghoshal
- Department of Gastroenterology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, 226 014 India
| | - Sanjeev Sachdeva
- Department of Gastroenterology, G B Pant Hospital, New Delhi, 110 002 India
| | - Ujjala Ghoshal
- Department of Microbiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, 226 014 India
| | - Asha Misra
- Department of Gastroenterology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, 226 014 India
| | | | | | - Ayesha Shah
- University of Queensland, Faculty of Medicine, and Princess Alexandra Hospital, Department of Gastroenterology and Hepatology, Brisbane, Queensland, Australia
| | - M. Masudur Rahman
- Sheikh Russel National Gastroliver Institute and Hospital, Dhaka, Bangladesh
| | - Kok Ann Gwee
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore ,Stomach, Liver and Bowel Centre, Gleneagles Hospital, Singapore, Singapore
| | - Victoria P Y Tan
- Faculty of Medicine, University of Hong Kong, Pok Fu Lam, Hong Kong
| | - Tahmeed Ahmed
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Yeong Yeh Lee
- School of Medical Sciences, Universiti Sains Malaysia, Kota Bharu, Malaysia ,GI Function and Motility Unit, Hospital Universiti Sains Malaysia, Kota Bharu, Malaysia
| | - B S Ramakrishna
- SIMS Institute of Gastroenterology, Hepatology, and Transplantation, SRM Institutes for Medical Science, Chennai, 600 026 India
| | - Rupjyoti Talukdar
- Department of Gastroenterology, Asian Institute of Gastroenterology, Hyderabad, 500 082 India
| | - S V Rana
- Department of Biochemistry, All India Institute of Medical Sciences, Rishikesh, 249 203 India
| | - Saroj K Sinha
- Department of Gastroenterology, Postgraduate Institute of Medical Education and Research, Chandigarh, 160 012 India
| | - Minhu Chen
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Nayoung Kim
- Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seoul, South Korea
| | - Gerald Holtmann
- University of Queensland, Faculty of Medicine, and Princess Alexandra Hospital, Department of Gastroenterology and Hepatology, Brisbane, Queensland, Australia
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13
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Abstract
The term "small intestinal bacterial overgrowth" (SIBO) has been used to refer to a disorder resulting from the colonization of the small bowel by an increased number of microorganisms or by the presence of bacteria that are not usual constituents of this part of the gastrointestinal tract. Clinical presentations, often in patients with certain risk factors, can range from a full-blown malabsorption syndrome to such "functional" complaints as bloating and flatulence. SIBO is diagnosed by either culture of a small bowel aspirate or one of several breath tests. Treatment of SIBO entails risk factor modification, correction of nutritional deficiencies, and oral antibiotics.
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Affiliation(s)
- Daniel Bushyhead
- Division of Gastroenterology and Hepatology, Lynda K and David M Underwood Center for Digestive Disorders, Houston Methodist Hospital, 6550 Fannin Street Suite 1201, Houston, TX 77030, USA.
| | - Eamonn M Quigley
- Division of Gastroenterology and Hepatology, Lynda K and David M Underwood Center for Digestive Disorders, Houston Methodist Hospital, 6550 Fannin Street Suite 1201, Houston, TX 77030, USA
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14
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Small Intestinal Bacterial Overgrowth in Functional Dyspepsia: A Systematic Review and Meta-Analysis. Am J Gastroenterol 2021; 116:935-942. [PMID: 33734110 DOI: 10.14309/ajg.0000000000001197] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Accepted: 01/22/2021] [Indexed: 12/11/2022]
Abstract
INTRODUCTION This systematic review and meta-analysis aimed to determine the role of small intestinal bacterial overgrowth (SIBO) in patients with functional dyspepsia (FD). METHODS Electronic databases were searched until July 2020 for studies reporting prevalence of SIBO in FD. The prevalence rates, odds ratio, and 95% confidence intervals (CIs) of SIBO in FD and controls were calculated. RESULTS Seven studies with 263 patients with FD and 84 controls were identified. The odds for SIBO in patients with FD were significantly higher as compared to that in controls (odds ratio = 4.3, 95% CI, 1.1-17.5, 4 studies, 234 participants); however, there was moderate heterogeneity in this analysis. Including high-quality, case-control studies (all using glucose breath tests [GBTs]), the risk of SIBO in patients with FD as compared to controls was 2.8 higher (95% CI 0.8-10.0, 3 studies, 200 participants) with minimal heterogeneity in this analysis. Using the lactulose breath test, SIBO prevalence in FD was significantly higher (53.4%, 95% CI 33.9-71.9, 3 studies, 110 participants) as compared to that with GBT (17.2%, 95% CI 8.6-31.6, 4 studies, 153 participants). Substantial heterogeneity was found in studies using the lactulose breath test but not in studies using GBT. There was no significant difference in SIBO prevalence in patients with FD according to FD subtype. DISCUSSION This meta-analysis suggests a link between FD and SIBO. The quality of evidence is low and can be largely attributed to the type of breath test for SIBO diagnosis and clinical heterogeneity. More appropriately designed studies are required to confirm the link between SIBO and FD.
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15
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Requena T, Velasco M. The human microbiome in sickness and in health. Rev Clin Esp 2021; 221:233-240. [PMID: 31522775 DOI: 10.1016/j.rce.2019.07.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 07/08/2019] [Indexed: 12/18/2022]
Abstract
The study of the human microbiome has led to an exceptional increase in the current understanding of the importance of microbiota for health throughout all stages of life. Human microbial colonization occurs in the skin, genitourinary system and, mainly, in the oral cavity and intestinal tract. In these locations, the human microbiota establishes a symbiotic relationship with the host and helps maintain the physiological homeostasis. Lifestyle, age, diet and use of antibiotics are the main regulators of the composition and functionality of human microbiota. Recent studies have indicated the reduction in microbial diversity as one of the contributors to the development of diseases. In addition to phylogenetic diversity studies, further metagenomic studies are needed at the functional level of the human microbiome to improve our understanding of its involvement in human health.
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Affiliation(s)
- T Requena
- Departamento de Biotecnología y Microbiología de Alimentos, Instituto de Investigación en Ciencias de la Alimentación (CIAL-CSIC), Madrid, España.
| | - M Velasco
- Sección de Enfermedades Infecciosas, Medicina Interna, Hospital Universitario Fundación Alcorcón, Alcorcón, España
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16
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Holtmann G, Shah A, Morrison M. From trash to gold: gastrointestinal microbiome research in patients with functional gastrointestinal disorders. J Investig Med 2021. [DOI: 10.1136/jim-2021-001903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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17
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COLIGENTA treatment of small intestinal bacterial overgrowth. Results of an open study. Dig Liver Dis 2021; 53:66-71. [PMID: 33229276 DOI: 10.1016/j.dld.2020.10.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 10/15/2020] [Accepted: 10/25/2020] [Indexed: 12/11/2022]
Abstract
PURPOSE The treatment of small intestinal overgrowth (SIBO) varies according to the center. The present study aimed to evaluate the efficacy of COLIGENTA, an association of colimycin and gentamycin, on SIBO symptomatology and breath test normalization PATIENTS AND METHODS: In this prospective cross-sectional open study, 150 patients with functional bowel disorders and SIBO diagnosed by lactulose hydrogen breath test (LHBT) underwent COLIGENTA oral treatment. A new HLBT was performed 4 weeks after the first HLBT. RESULTS The patients were mainly female (74%), with a mean age of 47.4 ± 16.2 years and a body mass index of 26.2 ± 5.9 kg/m². After treatment, a decrease of expired hydrogen concentration (P<0.001) was found in the entire population. Improvement of gastrointestinal symptoms was found in 129 patients (86%), while the breath test's normalization was found in 62 patients (42%). Logistic regression showed that normalization of bowel symptoms was not associated with demographics, clinical, or hydrogen breath concentration. In contrast, normalization of LHBT was associated with an increase of breath hydrogen concentration at time 100 min during the first test (P = 0.003; OR=1.072; 95%CI= [1.023-1.123]). CONCLUSION The present study shows that 10-days of COLIGENTA treatment has a high SIBO clinical improvement rate and can be used as the first or second treatment line.
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18
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Shah A, Talley NJ, Koloski N, Macdonald GA, Kendall BJ, Shanahan ER, Walker MM, Keely S, Jones MP, Morrison M, Holtmann GJ. Duodenal bacterial load as determined by quantitative polymerase chain reaction in asymptomatic controls, functional gastrointestinal disorders and inflammatory bowel disease. Aliment Pharmacol Ther 2020; 52:155-167. [PMID: 32412673 DOI: 10.1111/apt.15786] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 02/12/2020] [Accepted: 04/20/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND Small intestinal bacterial overgrowth may play a role in gastrointestinal and non-gastrointestinal diseases. AIMS To use quantitative polymerase chain reaction (qPCR) to determine and compare bacterial loads of duodenal biopsies in asymptomatic controls, and patients with functional gastrointestinal disorders (FGIDs) and inflammatory bowel disease (IBD) including ulcerative colitis (UC) and Crohn's disease (CD). To define effects of gastric acid inhibition on bacterial load, explore links of bacterial load and gastrointestinal symptoms in response to a standardised nutrient challenge and compare bacterial load with glucose breath test results. METHODS In 237 patients (63 controls, 84 FGID and 90 IBD), we collected mucosal samples under aseptic conditions during endoscopy extracted and total DNA. Bacterial load metric was calculated utilising qPCR measurements of the bacterial 16S rRNA gene, normalised to human beta-actin expression. Standard glucose breath test and nutrient challenge test were performed. RESULTS The duodenal microbial load was higher in patients with FGID (0.22 ± 0.03) than controls (0.07 ± 0.05; P = 0.007) and patients with UC (0.01 ± 0.05) or CD (0.02 ± 0.09), (P = 0.0001). While patients treated with proton pump inhibitors (PPI) had significantly higher bacterial loads than non-users (P < 0.05), this did not explain differences between patient groups and controls. Bacterial load was significantly (r = 0.21, P < 0.016) associated with the symptom response to standardised nutrient challenge test. Methane, but not hydrogen values on glucose breath test were associated with bacterial load measured utilising qPCR. CONCLUSIONS Utilising qPCR, a diagnosis of FGID and treatment with PPI were independently associated with increased bacterial loads. Increased bacterial loads are associated with an augmented symptom response to a standardised nutrient challenge.
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Affiliation(s)
- Ayesha Shah
- Department of Gastroenterology and Hepatology, Princess Alexandra Hospital, Brisbane, Qld, Australia.,Faculty of Medicine and Faulty of Health and Behavioural Sciences, University of Queensland, Brisbane, Qld, Australia
| | - Nicholas J Talley
- Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW, Australia
| | - Natasha Koloski
- Department of Gastroenterology and Hepatology, Princess Alexandra Hospital, Brisbane, Qld, Australia.,Faculty of Medicine and Faulty of Health and Behavioural Sciences, University of Queensland, Brisbane, Qld, Australia
| | - Graeme A Macdonald
- Department of Gastroenterology and Hepatology, Princess Alexandra Hospital, Brisbane, Qld, Australia.,Faculty of Medicine and Faulty of Health and Behavioural Sciences, University of Queensland, Brisbane, Qld, Australia
| | - Bradley J Kendall
- Department of Gastroenterology and Hepatology, Princess Alexandra Hospital, Brisbane, Qld, Australia.,Faculty of Medicine and Faulty of Health and Behavioural Sciences, University of Queensland, Brisbane, Qld, Australia
| | - Erin R Shanahan
- Department of Gastroenterology and Hepatology, Princess Alexandra Hospital, Brisbane, Qld, Australia.,Faculty of Medicine and Faulty of Health and Behavioural Sciences, University of Queensland, Brisbane, Qld, Australia
| | - Marjorie M Walker
- Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW, Australia
| | - Simon Keely
- Faculty of Health and Medicine, University of Newcastle, Callaghan, NSW, Australia
| | - Michael P Jones
- Psychology Department, Macquarie University, Ryde, NSW, Australia
| | - Mark Morrison
- Department of Gastroenterology and Hepatology, Princess Alexandra Hospital, Brisbane, Qld, Australia.,Diamantina Institute, University of Queensland, Brisbane, Qld, Australia
| | - Gerald J Holtmann
- Department of Gastroenterology and Hepatology, Princess Alexandra Hospital, Brisbane, Qld, Australia.,Faculty of Medicine and Faulty of Health and Behavioural Sciences, University of Queensland, Brisbane, Qld, Australia
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Bogatyrev SR, Rolando JC, Ismagilov RF. Self-reinoculation with fecal flora changes microbiota density and composition leading to an altered bile-acid profile in the mouse small intestine. MICROBIOME 2020; 8:19. [PMID: 32051033 PMCID: PMC7017497 DOI: 10.1186/s40168-020-0785-4] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 01/05/2020] [Indexed: 05/06/2023]
Abstract
BACKGROUND The upper gastrointestinal tract plays a prominent role in human physiology as the primary site for enzymatic digestion and nutrient absorption, immune sampling, and drug uptake. Alterations to the small intestine microbiome have been implicated in various human diseases, such as non-alcoholic steatohepatitis and inflammatory bowel conditions. Yet, the physiological and functional roles of the small intestine microbiota in humans remain poorly characterized because of the complexities associated with its sampling. Rodent models are used extensively in microbiome research and enable the spatial, temporal, compositional, and functional interrogation of the gastrointestinal microbiota and its effects on the host physiology and disease phenotype. Classical, culture-based studies have documented that fecal microbial self-reinoculation (via coprophagy) affects the composition and abundance of microbes in the murine proximal gastrointestinal tract. This pervasive self-reinoculation behavior could be a particularly relevant study factor when investigating small intestine microbiota. Modern microbiome studies either do not take self-reinoculation into account, or assume that approaches such as single housing mice or housing on wire mesh floors eliminate it. These assumptions have not been rigorously tested with modern tools. Here, we used quantitative 16S rRNA gene amplicon sequencing, quantitative microbial functional gene content inference, and metabolomic analyses of bile acids to evaluate the effects of self-reinoculation on microbial loads, composition, and function in the murine upper gastrointestinal tract. RESULTS In coprophagic mice, continuous self-exposure to the fecal flora had substantial quantitative and qualitative effects on the upper gastrointestinal microbiome. These differences in microbial abundance and community composition were associated with an altered profile of the small intestine bile acid pool, and, importantly, could not be inferred from analyzing large intestine or stool samples. Overall, the patterns observed in the small intestine of non-coprophagic mice (reduced total microbial load, low abundance of anaerobic microbiota, and bile acids predominantly in the conjugated form) resemble those typically seen in the human small intestine. CONCLUSIONS Future studies need to take self-reinoculation into account when using mouse models to evaluate gastrointestinal microbial colonization and function in relation to xenobiotic transformation and pharmacokinetics or in the context of physiological states and diseases linked to small intestine microbiome and to small intestine dysbiosis. Video abstract.
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Affiliation(s)
- Said R Bogatyrev
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Justin C Rolando
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E. California Blvd, Pasadena, CA, USA
| | - Rustem F Ismagilov
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA.
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E. California Blvd, Pasadena, CA, USA.
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20
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Small Intestinal Bacterial Overgrowth in Irritable Bowel Syndrome: A Systematic Review and Meta-Analysis of Case-Control Studies. Am J Gastroenterol 2020; 115:190-201. [PMID: 31913194 DOI: 10.14309/ajg.0000000000000504] [Citation(s) in RCA: 83] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
INTRODUCTION We conducted a systematic review and meta-analysis to compare the prevalence of small intestinal bacterial overgrowth (SIBO) in patients with irritable bowel syndrome (IBS) and controls. METHODS Electronic databases were searched up to December 2018 for studies reporting SIBO prevalence in patients with IBS. Prevalence rates, odds ratios (ORs), and 95% confidence intervals (CIs) of SIBO in patients with IBS and controls were calculated. RESULTS We included 25 studies with 3,192 patients with IBS and 3,320 controls. SIBO prevalence in patients with IBS was significantly increased compared with controls (OR = 3.7, 95% CI 2.3-6.0). In studies using only healthy controls, the OR for SIBO in patients with IBS was 4.9 (95% CI 2.8-8.6). With breath testing, SIBO prevalence in patients with IBS was 35.5% (95% CI 33.6-37.4) vs 29.7% (95% CI 27.6-31.8) in controls. Culture-based studies yielded a SIBO prevalence of 13.9% (95% CI 11.5-16.4) in patients with IBS and 5.0% (95% CI 3.9-6.2) in controls with a cutoff value of 10 colony-forming units per milliliter vs 33.5% (95% CI 30.1-36.9) in patients with IBS and 8.2% (95% CI 6.8-9.6) in controls with a cutoff value of 10 colony-forming unit per milliliter, respectively. SIBO prevalence diagnosed by lactulose breath test is much greater in both patients with IBS (3.6-fold) and controls (7.6-fold) compared with glucose breath test. Similar difference is seen when lactulose breath test is compared with culture methods. OR for SIBO in patients with IBS-diarrhea compared with IBS-constipation was 1.86 (95% CI 1.83-2.8). Methane-positive breath tests were significantly more prevalent in IBS-constipation compared with IBS-diarrhea (OR = 2.3, 95% CI 1.2-4.2). In patients with IBS, proton pump inhibitor was not associated with SIBO (OR = 0.8, 95% CI 0.5-1.5, P = 0.55). DISCUSSION This systematic review and meta-analysis suggests a link between IBS and SIBO. However, the overall quality of the evidence is low. This is mainly due to substantial "clinical heterogeneity" due to lack of uniform selection criteria for cases and controls and limited sensitivity and specificity of the available diagnostic tests.
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21
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The human microbiome in sickness and in health. Rev Clin Esp 2020; 221:233-240. [PMID: 33998505 DOI: 10.1016/j.rceng.2019.07.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 07/08/2019] [Indexed: 01/22/2023]
Abstract
The study of the human microbiome has led to an exceptional increase in the current understanding of the importance of microbiota for health throughout all stages of life. Human microbial colonization occurs in the skin, genitourinary system and, mainly, in the oral cavity and intestinal tract. In these locations, the human microbiota establishes a symbiotic relationship with the host and helps maintain physiological homeostasis. Lifestyle, age, diet and use of antibiotics are the main regulators of the composition and functionality of human microbiota. Recent studies have indicated the reduction in microbial diversity as one of the contributors to the development of diseases. In addition to phylogenetic diversity studies, further metagenomic studies are needed at the functional level of the human microbiome to improve our understanding of its involvement in human health.
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