Small Bowel Bacterial Overgrowth in Symptomatic Older People: Can It Be Diagnosed Earlier?

Gastric Acid Suppression Therapy and Its Association with Peritoneal Dialysis-Associated Peritonitis in the Peritoneal Dialysis Outcomes and Practice Patterns Study (PDOPPS)

Key Points

In a large multinational cohort of PD patients, any GAS use was not associated with an increased risk of all-organism peritonitis. For peritonitis, risks were particularly high among certain classes of organisms particularly for Gram-negative, enteric, and streptococcal peritonitis episodes. The association with enteric peritonitis appeared to be stronger among H2RA users.

Background

Peritonitis is a major peritoneal dialysis–related complication. We determined whether gastric acid suppression (GAS) (proton pump inhibitor [PPI] or histamine-2 receptor antagonists [H2RAs]) use was associated with all-cause and organism-specific peritonitis in peritoneal dialysis patients.

Methods

In the Peritoneal Dialysis Outcomes and Practice Patterns Study (595 facilities, eight countries, years 2014–2022), associations between GAS use and time to first episode of all-cause peritonitis were examined using Cox proportional hazards models. The primary exposure of interest was GAS and secondarily PPI or H2RA use. Secondary outcomes were organism-specific peritonitis, peritonitis cure rates, and death.

Results

Among patients (N =23,797) at study baseline, 6020 (25.3%) used PPIs, and 1382 (5.8%) used H2RAs. Overall risks of GAS use and peritonitis risk (adjusted hazard ratio [AHR]=1.05, 95% confidence interval [CI], 0.98 to 1.13]) and use of PPI (AHR 1.06 [95% CI, 0.99 to 1.14]) or H2RA (AHR 1.02 [95% CI, 0.88 to 1.18]) did not reach statistical significance. In organism-specific analyses, GAS users displayed higher peritonitis risks for Gram-negative (AHR 1.29, 95% CI, 1.05 to 1.57), Gram-positive (AHR 1.15, 95% CI, 1.01 to 1.31), culture-negative (AHR 1.20, 95% CI, 1.01 to 1.42), enteric (AHR 1.23, 95% CI, 1.03 to 1.48), and particularly Streptococcal (AHR 1.47, 95% CI, 1.15 to 1.89) peritonitis episodes. GAS was also associated with higher overall mortality (AHR 1.13 [95% CI, 1.05 to 1.22]).

Conclusion

The association between GAS use and peritonitis risk was weaker (hazard ratio [HR] 1.05 [0.98 to 1.13]) than for streptococcal (HR 1.57 [1.15 to 1.89]) and Gram-negative (HR 1.29 [1.05 to 1.57]) peritonitis. A better understanding of mechanisms surrounding the differential effects of GAS subtype on peritonitis risks is needed. Clinicians should be cautious when prescribing GAS. The impact of GAS deprescribing on peritonitis risk requires further evaluation.

Small intestinal bacterial overgrowth: current update

PURPOSE OF REVIEW

This article aims to provide an up-to-date review of small intestinal bacterial overgrowth (SIBO), including etiology and risk factors, clinical manifestations, diagnostic evaluation for suspected SIBO, and therapeutic options.

RECENT FINDINGS

Recent advances in breath testing, capsule and urine-based testing have opened new avenues and improved diagnostic yield of SIBO. Nonantibiotic-based treatment strategies have shown promising results in initial trials.

SUMMARY

Small intestinal bacterial overgrowth (SIBO) is a condition defined by the excess bacteria or changes in bacterial composition of the small intestine. These are associated with various gastrointestinal (GI) symptoms such as bloating, abdominal distension, diarrhea, nutrient deficiencies, and even frank weight loss. Small bowel jejunal aspirate of >10 5 CFU/ml has traditionally been considered the gold standard for diagnosis. Glucose and lactulose breath testing have become more common in clinical practice as they are noninvasive, easily accessible, and have lower cost. Treatment focuses on the eradication of excess bacteria in the small bowel and is traditionally done with the use of oral antibiotics. Other emerging therapies may include probiotics, diet manipulation, and prokinetic agents.

Chronic loose stools following right-sided hemicolectomy for colon cancer and the association with bile acid malabsorption and small intestinal bacterial overgrowth

AIM

Patients treated with right-sided hemicolectomy for colon cancer may suffer from long-term bowel dysfunction, including loose stools, urgency and faecal incontinence. The underlying causes are poorly understood. The aim of this case-control study was to investigate the aetiology of chronic loose stools among patients with right-sided hemicolectomy curatively operated for cancer.

METHOD

Cases with chronic loose stools (Bristol stool type 6-7) after right-sided hemicolectomy were compared with a control group of patients with right-sided hemicolectomy without loose stools. All patients underwent a selenium-75 homocholic acid taurine (SeHCAT) scan to diagnose bile acid malabsorption (BAM) and a glucose breath test to diagnose small intestinal bacterial overgrowth (SIBO). Gastrointestinal transit time (GITT) was assessed with radiopaque markers. In a subgroup of patients, fibroblast growth factor 19 (FGF19) was measured in fasting blood. SIBO was treated with antibiotics and BAM was treated with bile acid sequestrants.

RESULTS

We included 45 cases and 19 controls. In the case group, 82% (n = 36) had BAM compared with 37% (n = 7) in the control group, p < 0.001. SIBO was diagnosed in 73% (n = 33) of cases with chronic loose stools and in 74% (n = 14) of controls, p = 0.977. No association between BAM and SIBO was observed. GITT was similar in cases and controls. No difference in median FGF19 was observed between cases and controls (p = 0.894), and no correlation was seen between FGF19 and SeHCAT retention (r_s 0.20, p = 0.294). Bowel symptoms among cases were reduced after treatment.

CONCLUSION

BAM and SIBO are common in patients having undergone right-sided hemicolectomy for cancer. Chronic loose stools were associated with BAM but not with SIBO.

Chronic Intestinal Pseudo-Obstruction Is Associated with Intestinal Methanogen Overgrowth

BACKGROUND

Chronic intestinal pseudo-obstruction (CIP) is a rare motility disorder characterized by dilated small bowel in the absence of mechanical obstruction. CIP has a known association with small intestinal bacterial overgrowth (SIBO); however, data regarding association with specific subtypes such as methane-positive (M+) and hydrogen-positive (H+) SIBO are limited. Therefore, we conducted this study to characterize subtypes of SIBO in CIP and compare them with non-CIP patients.

AIMS

The aim is to explore the association and prevalence of hydrogen and methane subtypes of SIBO in patients with CIP.

METHODS

A retrospective chart review was conducted for 494 patients who underwent glucose breath tests (GBT) in 2019. CIP was diagnosed based on clinical suspicion and after ruling out mechanical obstruction. We also reviewed demographic data, including age, gender, body mass index, tobacco and alcohol history, medical comorbidities, use of proton pump inhibitors, and history of colectomy.

RESULTS

Among 494 patients, 7.7% (38) had CIP. The prevalence of M+ GBT in CIP patients was higher compared with non-CIP patients, and it was significant [52.6% (20/38) versus 11.8% (54/456), p < 0.001]. The prevalence of H+ GBT in our cohort of CIP patients was similar to that of non-CIP patients [23.7% (9/38) versus 25.7% (117/456), p = 0.941].

CONCLUSION

The prevalence of methane-positive GBT was higher in CIP patients than in patients without CIP. This finding further strengthens the hypothesis that the relationship between motility disorders and methanogen overgrowth is facilitative.

Understanding Cystic Fibrosis Comorbidities and Their Impact on Nutritional Management

Cystic fibrosis (CF) is a chronic, multisystem disease with multiple comorbidities that can significantly affect nutrition and quality of life. Maintaining nutritional adequacy can be challenging in people with cystic fibrosis and has been directly associated with suboptimal clinical outcomes. Comorbidities of CF can result in significantly decreased nutritional intake and intestinal absorption, as well as increased metabolic demands. It is crucial to utilize a multidisciplinary team with expertise in CF to optimize growth and nutrition, where patients with CF and their loved ones are placed in the center of the care model. Additionally, with the advent of highly effective modulators (HEMs), CF providers have begun to identify previously unrecognized nutritional issues, such as obesity. Here, we will review and summarize commonly encountered comorbidities and their nutritional impact on this unique population.

Asian-Pacific consensus on small intestinal bacterial overgrowth in gastrointestinal disorders: An initiative of the Indian Neurogastroenterology and Motility Association

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.

Small intestinal bacterial overgrowth in Alzheimer's disease

The results of animal studies and clinical data support the gut microbiota contribution to the pathogenesis of Alzheimer’s disease (AD). The aim of this pilot study was to evaluate the prevalence of small intestinal bacterial overgrowth (SIBO) and fecal markers of intestinal inflammation and permeability in AD patients. The study was conducted in 45 AD patients and 27 controls. Data on comorbidities, pharmacotherapy, and gastrointestinal symptoms were acquired from medical records and a questionnaire. SIBO was evaluated using lactulose hydrogen breath test. Fecal calprotectin and zonulin levels were assessed by ELISA assays. The positive result of SIBO breath test was found in 49% of the AD patients and 22% of the controls (p = 0.025). The comparative analysis between SIBO-positive and SIBO-negative AD patients with respect to the degree of cognitive impairment, comorbidities and used medications did not reveal any statistically significant difference, except for less common heartburn in SIBO-positive AD patients than in SIBO-negative ones (9 vs 35%, p = 0.038). The median fecal calprotectin and zonulin levels in the AD group compared to the control group amounted to 43.1 vs 64.2 µg/g (p = 0.846) and 73.5 vs 49.0 ng/ml (p = 0.177), respectively. In the AD patients there was no association between the presence of SIBO and fecal calprotectin level. Patients with AD are characterized by higher prevalence of SIBO not associated with increased fecal calprotectin level that may be related to anti-inflammatory effect of cholinergic drugs used in the treatment of AD.

Predictors of Small Intestinal Bacterial Overgrowth in Symptomatic Patients Referred for Breath Testing

Background

Indications for a breath test (BT) are well established in the symptomatic patient with risk factors predisposing them to small intestinal bacterial overgrowth (SIBO). Characteristics and the profile of this population are not well known. Our objective was to study the characteristics of patients undergoing a BT for SIBO and to identify factors associated with a positive BT.

Methods

Retrospective study was conducted from 2012 to 2016 at the neurogastroenterology unit of the Centre Hospitalier de l'Universite de Montreal (CHUM). All patients who completed a BT (lactulose and/or glucose) were included. Demographics and clinical factors were analyzed to identify predictors of positive BT. Type of antibiotic treatment and clinical response were compiled. Groups of patients with (SIBO⁺) and without SIBO (SIBO^-) were also compared.

Results

A total of 136 patients were included in the study (mean age 51.2, range 20 - 80 years; 63% women), and SIBO was detected in 33.8% (n = 46). Both groups were similar in terms of age, body mass index, and gender. SIBO was significantly associated with the presence of abdominal pain (odds ratio (OR) = 4.78; P < 0.05), bloating (OR = 5.39; P < 0.05), smoking (OR = 6.66; P < 0.05), and anemia (OR = 4.08; P < 0.05). No association was identified with gender, age, obesity, and risk factors for SIBO. Antibiotics were used in 43% of patients with a positive BT, but clinical response was not significantly different in the subgroup that received antibiotics versus the subgroup that did not.

Conclusions

The prevalence of SIBO is high in symptomatic patients who underwent breath testing. Abdominal pain, bloating, smoking, and anemia are strongly associated with SIBO. Treatment of SIBO with antibiotics needs to be further investigated to better determine its efficacy on gastrointestinal symptoms.

Gastric Acid Suppression and the Risk of Enteric Peritonitis in Peritoneal Dialysis Patients

Objective

Peritonitis caused by enteric organisms in peritoneal dialysis (PD) patients is associated with greater morbidity and mortality than peritonitis with non-enteric organisms. One reported risk factor for enteric peritonitis (EP) is gastric acid suppression, with two small studies providing conflicting results. The objective of this study was to determine, using a larger patient population, whether gastric acid suppressants are associated with an increased risk of EP.

Patients and Methods

Using a single-center case-control design, information on episodes of EP occurring between 2003 and 2006 was collected. Control episodes were all non-enteric episodes of peritonitis that occurred during the same time interval. Proton pump inhibitor (PPI) or H2-blocker (H2B) use prior to development of peritonitis was documented.

Results

A total of 228 peritonitis episodes among 137 patients met inclusion criteria. In 32% of episodes, the causative organism was enteric. Gastric acid suppressant use was documented in 46% of episodes, with the majority on PPIs. Overall, gastric acid suppression was not associated with a higher EP risk ( p = 0.17). In a post hoc analysis, PPIs were not associated with EP [odds ratio (OR) 1.3, 95% confidence interval (CI) 0.7 – 2.4; p = 0.42], whereas H2Bs were associated with a higher risk of EP (OR 2.9, 95% CI 1.1 – 7.7; p = 0.04), although the number of patients on H2Bs was small.

Conclusion

Overall, gastric acid suppression was not associated with an increased risk of peritonitis with enteric organisms. While PPI use appears to be safe for PD patients with appropriate indications, the potential risk of EP with H2Bs requires further investigation.

Small Intestinal Bacterial Overgrowth in Children: A State-Of-The-Art Review

Small intestinal bacterial overgrowth (SIBO) is a heterogenous and poorly understood entity characterised by an excessive growth of select microorganisms within the small intestine. This excessive bacterial biomass, in turn, disrupts host physiology in a myriad of ways, leading to gastrointestinal and non-gastrointestinal symptoms and complications. SIBO is a common cause of non-specific gastrointestinal symptoms in children, such as chronic abdominal pain, abdominal distention, diarrhoea, and flatulence, amongst others. In addition, it has recently been implicated in the pathophysiology of stunting, a disease that affects millions of children worldwide. Risk factors such as acid-suppressive therapies, alterations in gastrointestinal motility and anatomy, as well as impoverished conditions, have been shown to predispose children to SIBO. SIBO can be diagnosed via culture-dependant or culture-independent approaches. SIBO's epidemiology is limited due to the lack of uniformity and consensus of its diagnostic criteria, as well as the paucity of literature available. Antibiotics remain the first-line treatment option for SIBO, although emerging modalities such as probiotics and diet manipulation could also have a role. Herein, we present a state-of-the-art-review which aims to comprehensively outline the most current information on SIBO in children, with particular emphasis on the gut microbiota.

Long-term Functional Outcome After Right-Sided Complete Mesocolic Excision Compared With Conventional Colon Cancer Surgery: A Population-Based Questionnaire Study

BACKGROUND

Complete mesocolic excision improves the long-term outcome of colon cancer but might carry a risk of bowel dysfunction.

OBJECTIVE

This study aimed to investigate whether right-sided complete mesocolic excision is associated with an increased risk of long-term bowel dysfunction and reduced quality of life compared with conventional colon cancer resections.

DESIGN

Data were extracted from a population-based study comparing complete mesocolic excision and conventional colon cancer resections and from a national questionnaire survey regarding functional outcome.

SETTINGS

Elective right-sided colon resections for stage I to III colon adenocarcinoma were performed at 4 university colorectal centers between June 2008 and December 2014.

PATIENTS

Seven hundred sixty-two patients were eligible to receive the questionnaire in November 2015.

MAIN OUTCOME MEASURES

The primary outcomes measured were the risk of diarrhea (Bristol stool scale score of 6-7), 4 or more bowel movements daily, and the impact of bowel function on quality of life. Secondary outcomes were other bowel symptoms, chronic pain, and quality of life measured by the European Organisation for Research and Treatment of Cancer QLQ-C30.

RESULTS

One hundred forty-one (63.8%) and 324 (59.9%) patients undergoing complete mesocolic excision and conventional resections responded after a median of 3.99 (interquartile range, 2.11-5.32) and 4.11 (interquartile range, 3.01-5.53) years (p = 0.04). Complete mesocolic excision was not associated with increased risk of diarrhea (adjusted OR, 1.07; 95% CI, 0.57-1.95; p = 0.84), 4 or more bowel movements daily (adjusted OR, 1.16; 95% CI, 0.57-2.24; p = 0.68), or lower quality of life (adjusted OR, 0.84; 95% CI, 0.49-1.40; p = 0.50). Complete mesocolic excision was associated nonsignificantly with nocturnal bowel movements, but not associated with chronic pain or other secondary outcomes.

LIMITATIONS

This study was limited by the retrospective design with unknown baseline symptoms. Responding patients were younger but without obvious selection bias. The outcome "diarrhea" seemed somehow sensitive to information bias.

CONCLUSION

Right-sided complete mesocolic excision seems associated with neither bowel dysfunction nor impaired quality of life when compared with conventional surgery. See Video Abstract at http://links.lww.com/DCR/A665.

Prevalence and predictors of small intestinal bacterial overgrowth in irritable bowel syndrome: a systematic review and meta-analysis

BACKGROUND

The reported prevalence of small intestinal bacterial overgrowth (SIBO) among individuals with irritable bowel syndrome (IBS) is highly variable. The aim of the study is to estimate the prevalence and identify predictors of SIBO in IBS.

METHODS

PubMed, Cochrane Library, and EMBASE through July 2017 were searched to identify studies evaluating the prevalence of SIBO in IBS. The pooled prevalence of SIBO among individuals with IBS and the pooled odds ratio (OR) of SIBO among those with IBS compared with healthy controls were calculated. Predictors of SIBO among IBS patients were also evaluated.

RESULTS

Fifty studies (8398 IBS, 1432 controls) met the inclusion criteria. Overall pooled prevalence of SIBO in IBS was 38% (95% CI 32-44) and was higher among individuals with IBS (OR 4.7, 95% CI 3.1-7.2) compared with controls. The pooled prevalence of SIBO in IBS was higher in studies diagnosed by breath tests (40%, 95% CI 33-46) compared with cultures (19%, 95% CI 8-30). Among those with IBS, female gender (OR 1.5, 95% CI 1.0-2.1), older age (standard mean difference 3.1 years, 95% CI 0.9-5.4), and IBS-diarrhea (OR 1.7, 95% CI 1.3-2.3) compared with other IBS subtypes increased the odds of SIBO; proton pump inhibitor (PPI) use (OR 1.1, 95% CI 0.7-1.7) was not associated with SIBO.

CONCLUSIONS

More than one-third of IBS patients tested positive for SIBO, and the odds of SIBO in IBS were increased by nearly fivefold. The prevalence of SIBO varied according to the diagnostic modality performed. Female gender, older age, and IBS-diarrhea, but not PPI use, were associated with SIBO among individuals with IBS.

Chronic diarrhoea following surgery for colon cancer-frequency, causes and treatment options

PURPOSE

The growing population of survivors after colon cancer warrants increased attention to the long-term outcome of surgical treatment. The change in bowel anatomy after resection disrupts normal gastrointestinal function and may cause symptoms. Thus, many patients surviving colon cancer have to cope with bowel dysfunction for the rest of their lives. We here aim to provide an overview of the literature on this topic.

METHODS

We review long-term functional outcomes of surgical treatment for colon cancer, the underlying pathology, and treatment options.

RESULTS

Common symptoms include constipation, urge for defecation and diarrhoea. Causes of diarrhoea after colon cancer surgery are sparsely studied, but they probably include bile acid malabsorption, small intestinal bacterial overgrowth and disruption of the ileal brake. Specific diagnosis should be made to allow individual treatment based on the underlying pathology. Studies on treatment of functional problems after surgery for colon cancer are extremely few, but some lessons can be drawn from the treatment of other patient groups having undergone colon surgery.

CONCLUSION

Diarrhoea is likely a common long-term complication after colon cancer surgery. Attention to this complication and a specific diagnosis will aid the targeted treatment of patients suffering from this complication.

Lactulose Hydrogen Breath Test Result Is Associated with Age and Gender

Small intestinal bacterial overgrowth (SIBO) is associated with chronic gastrointestinal diseases and structural/functional abnormalities of the gastrointestinal tract. SIBO's association with clinical characteristics is unclear. This study investigates the association between clinical factors and SIBO according to lactulose hydrogen breath test (LHBT) result. Methods. A cross-sectional study in a university-based gastroenterology practice was performed. Data was abstracted from the medical records of subjects undergoing LHBT from 6/1/2009 to 6/1/2013. Logistic regression analysis was performed to determine the association between predictor variables: age, sex, body mass index (BMI), and positive LHBT, the outcome of interest. Results. LHBT was performed in 791 subjects. Fifty-four percent had a positive LHBT. There was no statistically significant difference between the LHBT results according to age or BMI. In females, the likelihood of a positive LHBT increased with age (OR 1.02; 95% CI: 1.01–1.03). In males, the likelihood of a positive LHBT result decreased with age (OR 0.98; 95% CI: 0.97–1.00). Conclusion. There was an association between age, with respect to sex, and a positive LHBT. With increased age in females, the odds of a positive LHBT increased, while, in men, the odds of a positive LHBT decreased with age.

Prevalence of Small Intestinal Bacterial Overgrowth among Chronic Pancreatitis Patients: A Case-Control Study

Background. Patients with chronic pancreatitis (CP) exhibit numerous risk factors for the development of small intestinal bacterial overgrowth (SIBO). Objective. To determine the prevalence of SIBO in patients with CP. Methods. Prospective, single-centre case-control study conducted between January and September 2013. Inclusion criteria were age 18 to 75 years and clinical and radiological diagnosis of CP. Exclusion criteria included history of gastric, pancreatic, or intestinal surgery or significant clinical gastroparesis. SIBO was detected using a standard lactulose breath test (LBT). A healthy control group also underwent LBT. Results. Thirty-one patients and 40 controls were included. The patient group was significantly older (53.8 versus 38.7 years; P < 0.01). The proportion of positive LBTs was significantly higher in CP patients (38.7 versus 2.5%: P < 0.01). A trend toward a higher proportion of positive LBTs in women compared with men was observed (66.6 versus 27.3%; P = 0.056). The subgroups with positive and negative LBTs were comparable in demographic and clinical characteristics, use of opiates, pancreatic enzymes replacement therapy (PERT), and severity of symptoms. Conclusion. The prevalence of SIBO detected using LBT was high among patients with CP. There was no association between clinical features and the risk for SIBO.

Small intestinal bacterial overgrowth: duodenal aspiration vs glucose breath test

BACKGROUND

The diagnosis of small intestinal bacterial overgrowth (SIBO) remains challenging. Our aim was to examine the diagnostic yield of duodenal aspiration/culture and glucose breath test (GBT), and effects of gender, race and demographics on prevalence of SIBO.

METHODS

Patients with unexplained gas, bloating and diarrhea and negative endoscopy, imaging and blood tests were prospectively enrolled in two centers in USA. Randomly, within 1 week each patient underwent both duodenal aspiration/culture and GBT. The diagnostic yield of each test and relationship of symptoms, and effects of ethnicity, age, and gender on prevalence of SIBO were assessed and compared.

KEY RESULTS

Duodenal culture was positive in 62/139 (44.6%) subjects and GBT was positive in 38/139 (27.3%) subjects with an overall diagnostic agreement of 65.5%. The sensitivity, specificity, positive and negative predictive value of GBT was 42%, 84%, 68%, and 64%, respectively. Ethnicity or gender did not influence SIBO, but SIBO positive patients were older (p = 0.0018). Symptom patterns were similar except bloating was more prevalent in GBT positive and gas in culture positive subjects.

CONCLUSIONS & INFERENCES

Duodenal aspiration/culture identifies 45% of patients with suspected SIBO. GBT has lower sensitivity but good specificity for detection of SIBO. There were no ethnic or gender differences in the prevalence of SIBO, but patients with SIBO were older. Because GBT is non-invasive, it should be considered first in patients with suspected SIBO.

A Case of Blind Loop Syndrome Caused by Infection with Giardia duodenalis Diagnosed with Double Balloon Enteroscopy

A 75-year-old man who had undergone partial gastrectomy was referred to our hospital due to worsening leg edema, loose stools and malnutrition. Double balloon enteroscopy followed by insertion of an indwelling ileus tube was performed to investigate the microbial flora and for washing inside the blind loop. Trophozoites of Giardia were detected in the sampled fluid from the blind loop and DNA analysis disclosed an assemblage of genotype A-II of Giardia duodenalis. Treatment with oral metronidazole was effective. This case emphasizes the importance of a correct diagnosis when treating patients with blind loop syndrome in the digestive tract.

Augmented hepatic Toll-like receptors by fatty acids trigger the pro-inflammatory state of non-alcoholic fatty liver disease in mice

AIM

There is considerable evidence that intestinal microbiota are involved in the development of metabolic syndromes and, consequently, with the development of non-alcoholic fatty liver disease (NAFLD). Toll-like receptors (TLRs) are essential for the recognition of microbiota. However, the induction mechanism of TLR signals through the gut-liver axis for triggering the development of non-alcoholic steatohepatitis (NASH) or NAFLD remains unclear. In this study, we investigated the role of palmitic acid (PA) in triggering the development of a pro-inflammatory state of NAFLD.

METHODS

Non-alcoholic fatty liver disease was induced in mice fed a high fat diet (HFD). The mice were killed and the expression of TLRs, tumor necrosis factor (TNF), interleukin (IL)-1β, and phospho-interleukin-1 receptor-associated kinase 1 in the liver and small intestine were assessed. In addition, primary hepatocytes and Kupffer cells were treated with PA, and the direct effects of PA on TLRs induction by these cells were evaluated.

RESULTS

The expression of inflammatory cytokines such as TNF, IL-1β, and TLR-2, -4, -5, and -9 was increased in the liver, but decreased in the small intestine of HFD-fed mice in vivo. In addition, the expression of TLRs in primary hepatocytes and Kupffer cells was increased by treatment with PA.

CONCLUSION

In the development of the pro-inflammatory state of NAFLD, PA triggers the expression of TLRs, which contribute to the induction of inflammatory cytokines through TLR signals by intestinal microbiota.

Age-related changes in small intestinal mucosa epithelium architecture and epithelial tight junction in rat models

BACKGROUND AND AIMS

Functions of the intestinal mucosal barrier are often impaired in the elderly and are closely associated with many age-related diseases. However, mechanisms by which aging influences intestinal barrier function still remain unclear. The aim of this study was to investigate age-related changes in small intestinal morphology, bacteria contents and expression of epithelial tight junction (TJ) proteins.

METHODS

Thirty Sprague-Dawley rats were divided into groups: young (3 months), adult (12 months), and old (24 months). The small intestinal mucosal architecture and TJ of intestinal epithelial cells were examined by light microscopy and transmission electron microscopy. Jejunum and cecum contents were cultured to identify and measure bacterial species. mRNA expression of Zonula occludens-1 (ZO-1) and occludin were measured by semi-quantitative RT-PCR. Protein expression of ZO-1 and occludin were detected by immunohistochemistry and Western blot.

RESULTS

Normal ileum villi, which were thick and regularly arranged, though increasingly scattered and atrophic in character with shorter and narrower dimensions (P < 0.01), were observed in old rats, along with an elevated number of Gram-positive and Gram-negative bacteria in the jejunum. The TJs of intestinal epithelial cells, as detected by transmission electron microscopy, were wider and discontinuous in old rats. Age-induced down-regulation of mRNA expression and decreased protein expression of ZO-1 and occludin were observed in the ileum (P < 0.01).

CONCLUSIONS

Our study indicated that age-related intestinal barrier dysfunction may be associated with mucosal atrophy, damages to TJ structure, increased small intestine bacteria counts, and decreased epithelial TJ protein.

Long-term acid inhibition: benefits and harms

Proton pump inhibitors (PPIs) are the drugs of choice in the therapy of acid-related disorders. PPIs are as a class remarkably safe. Serious adverse events such as acute interstitial nephritis are extremely rare. Some reports in recent years have placed some concern on the long-term use of PPIs. Long-term therapy with PPIs can cause hypochlorhydria, hypergastrinemia and has interactions on hepatic cytochrome P450 enzymes which might increase the risk of infectious complications, nutritional deficiencies and drug-drug interactions. The vast majority of data came from retrospective case-control or cohort studies which are prone to confounders. At the moment we cannot conclude that long-term PPI use causes anemia, osteoporosis and bone fractures, increases the risk for pulmonary or enteric infections, has an effect on GUT mucosa, polyp or tumor formation, or that PPI use increases the risk of cardiovascular events in patients on PPIs and clopidogrel. We need prospective randomized trials to be able to definitely answer the questions raised in epidemiologic studies. Maintenance therapy with PPIs should be started only if strict indications for that therapy are fulfilled.

Clinical predictors of small intestinal bacterial overgrowth by duodenal aspirate culture

BACKGROUND

There has been increasing interest in small intestinal bacterial overgrowth (SIBO) after reports of a link with irritable bowel syndrome (IBS), yet our understanding of this entity is limited.

AIM

Our aim was to estimate the yield of patients undergoing duodenal aspirate culture, and to identify symptoms and features that predict SIBO.

METHODS

A medical chart review of patients who had undergone duodenal aspirate culture at an academic medical centre in 2003 was performed to record clinical characteristics and culture results. The associations between aspirate results and symptoms, medical diagnoses and medication use were assessed using logistic regression.

RESULTS

A total of 675 patients had available aspirate results. Mean age of the sample was 53 (s.d. 17) and 443 (66%) were female patients. Overall, 8% of aspirates were positive for SIBO; 2% of IBS patients had SIBO. Older age, steatorrhoea and narcotic use were associated with SIBO (P < 0.05). PPI use was not associated with SIBO, but was associated with bacterial growth not meeting criteria for SIBO (P < 0.05). Inflammatory bowel disease (IBD), small bowel diverticula and pancreatitis were positively associated with an abnormal duodenal aspirate (P < 0.05), but other conditions including IBS were not associated with SIBO.

CONCLUSION

Older age, steatorrhoea, narcotic use, IBD, small bowel diverticula and pancreatitis were associated with small intestinal bacterial overgrowth based on abnormal duodenal aspirate culture results. However, no clear associations of true small intestinal bacterial overgrowth with IBS or PPI use were detected, in contrast to recent speculation.

Small intestinal bacterial overgrowth in nonalcoholic steatohepatitis: association with toll-like receptor 4 expression and plasma levels of interleukin 8

BACKGROUND

Experimental and clinical studies suggest an association between small intestinal bacterial overgrowth (SIBO) and nonalcoholic steatohepatitis (NASH). Liver injury and fibrosis could be related to exposure to bacterial products of intestinal origin and, most notably, endotoxin, including lipopolysaccharide (LPS).

AIM

To compare the prevalence of SIBO and its relationships to LPS receptor levels and systemic cytokines in NASH patients and healthy control subjects.

METHODS

Eighteen NASH patients (eight males) and 16 age-matched and gender-matched healthy volunteers were studied. SIBO was assessed by the lactulose breath hydrogen test (LHBT), plasma lipopolysaccharide binding protein (LBP) levels by ELISA, and expression (as a percentage) of TLR-2 and 4 on CD14-positive cells by flow cytometry. Pro-inflammatory cytokines (IL-1β, IL-6, IL-8, and TNF-α) were measured in plasma.

RESULTS

SIBO was more common in NASH patients than control subjects (77.78% vs. 31.25%; P < 0.0001). LBP levels and TLR-2 expression were similar in both groups, TLR-4/MD-2 expression on CD14 positive cells was higher among NASH patients: expression, mean ± SEM, NASH vs. control: 20.95 ± 2.91% vs. 12.73 ± 2.29%, P < 0.05. Among the examined cytokines, only IL-8 levels were significantly higher in patients than control (P = 0.04) and correlated positively with TLR-4 expression (r = 0.5123, P = 0.036).

CONCLUSION

NASH patients have a higher prevalence of small intestinal bacterial overgrowth which is associated with enhanced expression of TLR-4 and release of IL-8. SIBO may have an important role in NASH through interactions with TLR-4 and induction of the pro-inflammatory cytokine, IL-8.

Small intestinal bacterial overgrowth syndrome

Human intestinal microbiota create a complex polymicrobial ecology. This is characterised by its high population density, wide diversity and complexity of interaction. Any dysbalance of this complex intestinal microbiome, both qualitative and quantitative, might have serious health consequence for a macro-organism, including small intestinal bacterial overgrowth syndrome (SIBO). SIBO is defined as an increase in the number and/or alteration in the type of bacteria in the upper gastrointestinal tract. There are several endogenous defence mechanisms for preventing bacterial overgrowth: gastric acid secretion, intestinal motility, intact ileo-caecal valve, immunoglobulins within intestinal secretion and bacteriostatic properties of pancreatic and biliary secretion. Aetiology of SIBO is usually complex, associated with disorders of protective antibacterial mechanisms (e.g. achlorhydria, pancreatic exocrine insufficiency, immunodeficiency syndromes), anatomical abnormalities (e.g. small intestinal obstruction, diverticula, fistulae, surgical blind loop, previous ileo-caecal resections) and/or motility disorders (e.g. scleroderma, autonomic neuropathy in diabetes mellitus, post-radiation enteropathy, small intestinal pseudo-obstruction). In some patients more than one factor may be involved. Symptoms related to SIBO are bloating, diarrhoea, malabsorption, weight loss and malnutrition. The gold standard for diagnosing SIBO is still microbial investigation of jejunal aspirates. Non-invasive hydrogen and methane breath tests are most commonly used for the diagnosis of SIBO using glucose or lactulose. Therapy for SIBO must be complex, addressing all causes, symptoms and complications, and fully individualised. It should include treatment of the underlying disease, nutritional support and cyclical gastro-intestinal selective antibiotics. Prognosis is usually serious, determined mostly by the underlying disease that led to SIBO.

Increased incidence of small intestinal bacterial overgrowth during proton pump inhibitor therapy

BACKGROUND & AIMS

Proton pump inhibitors (PPIs) can cause diarrhea, enteric infections, and alter the gastrointestinal bacterial population by suppressing the gastric acid barrier. Among patients that received long term PPI treatment, we evaluated the incidence of small intestinal bacterial overgrowth (SIBO; assessed by glucose hydrogen breath test [GHBT]), the risk factors for development of PPI-related SIBO and its clinical manifestations, and the eradication rate of SIBO after treatment with rifaximin.

METHODS

GHBTs were given to 450 consecutive patients (200 with gastroesophageal reflux disease who received PPIs for a median of 36 months; 200 with irritable bowel syndrome [IBS], in absence of PPI treatment for at least 3 years; and 50 healthy control subjects that had not received PPI for at least 10 years). Each subject was given a symptoms questionnaire.

RESULTS

SIBO was detected in 50% of patients using PPIs, 24.5% of patients with IBS, and 6% of healthy control subjects; there was a statistically significant difference between patients using PPIs and those with IBS or healthy control subjects (P < .001). The prevalence of SIBO increased after 1 year of treatment with PPI. The eradication rate of SIBO was 87% in the PPI group and 91% in the IBS group.

CONCLUSIONS

SIBO, assessed by GHBT, occurs significantly more frequently among long term PPI users than patients with IBS or control subjects. High dose therapy with rifaximin eradicated 87%-91% of cases of SIBO in patients who continued PPI therapy.

Safety of the long-term use of proton pump inhibitors

The proton pump inhibitors (PPIs) as a class are remarkably safe and effective for persons with peptic ulcer disorders. Serious adverse events are extremely rare for PPIs, with case reports of interstitial nephritis with omeprazole, hepatitis with omeprazole and lansoprazole, and disputed visual disturbances with pantoprazole and omeprazole. PPI use is associated with the development of fundic gland polyps (FGP); stopping PPIs is associated with regression of FGP. In the absence of Helicobacter pylori infection, the long-term use of PPIs has not been convincingly proven to cause or be associated with the progression of pre-existing chronic gastritis or gastric atrophy or intestinal metaplasia. Mild/modest hypergastrinemia is a physiological response to the reduction in gastric acid secretion due to any cause. The long-term use of PPIs has not been convincingly proven to cause enterochromaffin-like cell hyperplasia or carcinoid tumors. PPIs increase the risk of community acquired pneumonia, but not of hospital acquired (nosocomial) pneumonia. There is no data to support particular care in prescribing PPI therapy due to concerns about risk of hip fracture with the long-term use of PPIs. Long-term use of PPIs does not lead to vitamin B12 deficiencies, except possibly in the elderly, or in persons with Zollinger-Ellison Syndrome who are on high doses of PPI for prolonged periods of time. There is no convincingly proven data that PPIs increase the risk of Clostridium difficile-associated diarrhea in persons in the community. The discontinuation of PPIs may result in rebound symptoms requiring further and even continuous PPI use for suppression of symptoms. As with all medications, the key is to use PPIs only when clearly indicated, and to reassess continued use so that long-term therapy is used judiciously. Thus, in summary, the PPIs are a safe class of medications to use long-term in persons in whom there is a clear need for the maintenance of extensive acid inhibition.

Small intestinal bacterial overgrowth in irritable bowel syndrome: are there any predictors?

BACKGROUND

Small intestinal bacterial overgrowth (SIBO) is a condition in which excessive levels of bacteria, mainly the colonic-type species are present in the small intestine. Recent data suggest that SIBO may contribute to the pathophysiology of Irritable bowel syndrome (IBS). The purpose of this study was to identify potential predictors of SIBO in patients with IBS.

METHODS

Adults with IBS based on Rome II criteria who had predominance of bloating and flatulence underwent a glucose breath test (GBT) to determine the presence of SIBO. Breath samples were obtained at baseline and at 30, 45, 60, 75 and 90 minutes after ingestion of 50 g of glucose dissolved in 150 mL of water. Results of the glucose breath test, which measures hydrogen and methane levels in the breath, were considered positive for SIBO if 1) the hydrogen or methane peak was >20 ppm when the baseline was <10 ppm, or 2) the hydrogen or methane peak increased by 12 ppm when baseline was >or=10 ppm.

RESULTS

Ninety-eight patients were identified who underwent a GBT (mean age, 49 y; 78% female). Thirty-five patients (36%) had a positive GBT result suggestive of SIBO. A positive GBT result was more likely in patients >55 years of age (odds ratio [OR], 3.6; 95% confidence interval [CI], 1.4-9.0) and in females (OR, 4.0; 95% CI, 1.1-14.5). Hydrogen was detected more frequently in patients with diarrhea-predominant IBS (OR, 8; 95% CI, 1.4-45), and methane was the main gas detected in patients with constipation-predominant IBS (OR, 8; 95% CI, 1.3-44). There was no significant correlation between the presence of SIBO and the predominant bowel pattern or concurrent use of tegaserod, proton pump inhibitors, or opiate analgesics.

CONCLUSIONS

Small intestinal bacterial overgrowth was present in a sizeable percentage of patients with IBS with predominance of bloating and flatulence. Older age and female sex were predictors of SIBO in patients with IBS. Identification of possible predictors of SIBO in patients with IBS could aid in the development of successful treatment plans.

Probiotic yogurt in the elderly with intestinal bacterial overgrowth: endotoxaemia and innate immune functions

A study was conducted in healthy elderly living independently in senior housing to assess the impact of a probiotic yoghurt supplement on small intestinal bacterial overgrowth. Twenty-three participants with positive and thirteen participants with negative hydrogen breath test were studied before and after a period of 4 weeks of probiotic yoghurt administration. Intestinal permeability, plasma endotoxin levels, phagocytic activity of leucocytes, cytokine production by monocytes and free radical response of neutrophils were determined. Intestinal permeability was similar for the two groups and was unaffected by probiotic treatment. Both plasma endotoxin levels and the basal phagocytic activity of leucocytes decreased after yoghurt intake in the two groups. Exposure of monocytes and neutrophils ex vivo led to an increased cytokine response and free radical response, respectively. The normalisation of the various cytokine responses was more apparent in the group with positive breath test. In addition, the plasma levels of lipoplysaccharide binding protein and soluble CD14, lipoplysaccharide pattern recognition receptors and surrogate markers of lipoplysaccharide permeability were diminished by the end of the study. In conclusion, probiotic administration in the elderly normalises the response to endotoxin, and modulates activation markers in blood phagocytes, and therefore may help reduce low-grade chronic inflammation.

Hydrogen breath testing in adults: what is it and why is it performed?

A hydrogen breath test is a safe, easy-to-perform, 2-to 3-hour outpatient procedure used to identify the presence of small intestine bacterial overgrowth, evaluate carbohydrate maldigestion or malabsorption, and measure intestinal transit time. Breath sample analysis can reveal bacterial overgrowth in the small intestine by the characteristic early rise in breath hydrogen concentration (i.e., an earlier-than-expected rise at approximately 90 minutes when the substrate reaches the colon). Patients with irritable bowel syndrome are often referred for a hydrogen breath test because of symptoms of abdominal bloating, cramping, and diarrhea that are also characteristic of bacterial overgrowth. The elderly are at greater risk for nutritional compromise from untreated small intestine bacterial overgrowth than are younger patients. Treatment often consists of one or more courses of antibiotics. Most patients experience a reduction in symptoms with treatment.

Prevalence of small intestine bacterial overgrowth diagnosed by quantitative culture of intestinal aspirate in celiac disease

BACKGROUND AND AIM

A recent study using lactulose hydrogen-breath testing suggests that small intestine bacterial overgrowth (SIBO) is a common cause of nonresponsive celiac disease (CD). The prevalence of SIBO in CD diagnosed by quantitative culture of intestinal aspirate is unknown. The aim of this study is to evaluate the prevalence and significance of SIBO in CD based on the results of quantitative culture of intestinal aspirate.

METHODS

We studied patients with CD in whom culture of intestinal aspirate was evaluated for the presence of anaerobes and aerobes. Bacterial overgrowth was diagnosed if culture demonstrated >10 colony forming units/mL. The causes of nonresponsive CD were investigated.

RESULTS

We included 149 biopsy-confirmed CD patients. The intestinal aspirate was collected in 79 (53%) patients with nonresponsive CD, 47 (32%) as initial work-up for malabsorption, and in 23 (15%) asymptomatic treated CD. SIBO was diagnosed in 14 (9.3%). Nine (11%) with nonresponsive CD, 5 (11%) at initial work-up for malabsorption, and 0 in asymptomatic treated CD. Patients with a positive culture had evidence of worse malabsorption. A coexistent disorder was found in 67% of patients with both nonresponsive CD and bacterial overgrowth.

CONCLUSIONS

The prevalence of SIBO diagnosed by quantitative culture of intestinal aspirate was 9.3% in patients with CD. Patients with symptomatic treated or untreated CD were affected. SIBO may coexist with other disorders associated with nonresponsive CD.

Critical evaluation of diagnosing bacterial overgrowth in the proximal small intestine

BACKGROUND

Clinical small bowel bacterial overgrowth (SBBO) syndrome can be objectified by bacterial overgrowth tests. As direct culture of jejunal aspirates has disadvantages, noninvasive tests such as breath tests (BTs) are used. Major drawback of lactulose BT might be rapid lactulose transit to the colon. We evaluated diagnosing bacterial overgrowth using experimental and standard BT, and culture and molecular-based methods.

STUDY

Bacterial overgrowth was analyzed in 11 controls and 15 SBBO predisposed subjects. During experimental breath testing, an occlusive balloon limited lactulose to the small intestine. Jejunal fluid was analyzed using culture and molecular-based methods. Bacterial overgrowth was diagnosed on the basis of 20 ppm hydrogen or methane increase above baseline within 90 minutes or more than 10 CFU/mL excluding lactobacilli and streptococci and furthermore using all published definitions.

RESULTS

Experimental and standard BT showed no changes in timing of hydrogen excretion between controls and SBBO subjects. Using standard BT, 3/11 controls and 8/15 SBBO subjects were bacterial overgrowth positive. Total counts showed no significant differences between controls and SBBO subjects using culture and molecular-based methods. Bacterial overgrowth was diagnosed in 0/9 controls and 4/12 SBBO subjects using culture-based methods. Other definitions used in literature revealed no significant differences between controls and SBBO subjects.

CONCLUSIONS

In a small group of subjects, the experimental BT did not improve the ability of lactulose BT to diagnose bacterial overgrowth. Culturing showed less bacterial overgrowth in controls compared with BT. Remarkably, current diagnostic criteria do not seem to be accurate in discriminating between SBBO subjects and controls.

High prevalence of small intestinal bacterial overgrowth in patients with morbid obesity: a contributor to severe hepatic steatosis

BACKGROUND

With the increasing prevalence of obesity, non-alcoholic fatty liver disease (NAFLD) has become a major cause of liver diseases. Small intestinal bacterial overgrowth (SIBO) could be related to NAFLD. Our aim was to determine the prevalence of SIBO and its relationship with liver lesions in morbidly obese patients.

METHODS

A glucose hydrogen (H(2)) breath test (positive if fasting breath H(2) concentration > 20 ppm and/or an increase of > 10 ppm over baseline within the first 2 h) was performed in obese patients referred for bariatric surgery (body mass index [BMI] > 40 kg/m(2) or > 35 in association with comorbidities) and in healthy non-obese subjects. In obese patients, a surgical liver biopsy was performed.

RESULTS

One hundred and forty-six patients (129 women, age [mean+/-SE]: 40.7 +/- 11.4 years) were prospectively included in the study. The mean BMI was 46.1+/-6.4 kg/m(2). A liver biopsy was available in 137 patients and a breath test in 136. The frequency of positive breath tests was higher in obese patients (24/136, 17.1%) than in healthy subjects (1/40, 2.5%; P=0.031). In the univariate analysis, SIBO was not associated with clinical variables, but tended to be associated with more frequent severe hepatic steatosis (26.3 vs. 10.3%, P=0.127), whereas the frequency of sinusoidal or portal fibrosis, lobular necrosis and non-alcoholic steatohepatitis (NASH) were not different. In the multivariate analysis, SIBO (P=0.005) and the presence of a metabolic syndrome (P=0.006) were independent factors of severe hepatic steatosis.

CONCLUSION

In morbidly obese patients, bacterial overgrowth prevalence is higher than in healthy subjects and is associated with severe hepatic steatosis.

Myelo-optico-neuropathy in copper deficiency occurring after partial gastrectomy. Do small bowel bacterial overgrowth syndrome and occult zinc ingestion tip the balance?

Acquired copper deficiency has recently been recognized as a cause of myeloneuropathy mimicking subacute combined degeneration due to vitamin B-12 deficiency. A remote history of gastric surgery is frequently associated with this syndrome. However, the very limited prevalence of severe copper deficiency in patients with a history of gastric surgery suggests that additional contributing factors are likely to be involved. We describe a patient with copper deficiency and a previous Billroth II partial gastrectomy for gastric carcinoma, presenting with severe myelo-optico-neuropathy, demyelinating lesions of the brain, and subjective hyposmia. An abnormal glucose breath test also revealed small bowel bacterial overgrowth syndrome. Copper replacement therapy associated with antibiotic therapy was effective in preventing further neurological damage and in obtaining mild improvement. We propose that copper status should be evaluated in all patients presenting with unexplained noninflammatory myeloneuropathy. Small bowel bacterial overgrowth syndrome should be investigated as a cause of generalized malabsorption and a possible contributing factor to copper deficiency after gastric surgery, as should occult zinc ingestion.