Ernesto Cristiano Lauritano

Abnormal breath tests to lactose, fructose and sorbitol in irritable bowel syndrome may be explained by small intestinal bacterial overgrowth.

Background : Small intestinal bacterial overgrowth and sugar malabsorption (lactose, fructose, sorbitol) may play a role in irritable bowel syndrome. The lactulose breath test is a reliable and non‐invasive test for the diagnosis of small intestinal bacterial overgrowth. The lactose, fructose and sorbitol hydrogen breath tests are widely used to detect specific sugar malabsorption.

Hydrogen glucose breath test to detect small intestinal bacterial overgrowth: a prevalence case–control study in irritable bowel syndrome

Background:  Studies assessing the prevalence of small intestinal bacterial overgrowth in irritable bowel syndrome gave contrasting results. Differences in criteria to define irritable bowel syndrome patients and methods to assess small intestinal bacterial overgrowth may explain different results. Moreover, no data exist on small intestinal bacterial overgrowth prevalence in a significant population of healthy non‐irritable bowel syndrome subjects.

-Rifaximin dose-finding study for the treatment of small intestinal bacterial overgrowth

Background : Few controlled studies assessing choice and duration of antibiotic therapy for small intestinal bacterial overgrowth are available.

Small Intestinal Bacterial Overgrowth: Diagnosis and Treatment

Small intestinal bacterial overgrowth (SIBO) is a clinical condition characterized by a malabsorption syndrome due to an increase in microorganisms within the small intestine. The main mechanisms restricting bacterial colonization in the upper gut are the gastric acid barrier, mucosal and systemic immunity and intestinal clearance. When these mechanisms fail, bacterial overgrowth develops. Diarrhea, steatorrhea, chronic abdominal pain, bloating and flatulence are common symptoms and are similar to those observed in irritable bowel syndrome. Breath tests (glucose and/or lactulose breath tests) have been proposed as a sensitive and simple tool for the diagnosis of bacterial overgrowth, being non-invasive and inexpensive compared to the gold standard represented by the culture of intestinal aspirates. Antibiotic therapy is the cornerstone of SIBO treatment. Current SIBO treatment is based on empirical courses of broad-spectrum antibiotics since few controlled studies concerning the choice and duration of antibiotic therapy are available at present.

The role of small intestinal bacterial overgrowth in Parkinson's disease

Parkinsons disease is associated with gastrointestinal motility abnormalities favoring the occurrence of local infections. The aim of this study was to investigate whether small intestinal bacterial overgrowth contributes to the pathophysiology of motor fluctuations. Thirty‐three patients and 30 controls underwent glucose, lactulose, and urea breath tests to detect small intestinal bacterial overgrowth and Helicobacter pylori infection. Patients also underwent ultrasonography to evaluate gastric emptying. The clinical status and plasma concentration of levodopa were assessed after an acute drug challenge with a standard dose of levodopa, and motor complications were assessed by Unified Parkinsons Disease Rating Scale–IV and by 1‐week diaries of motor conditions. Patients with small intestinal bacterial overgrowth were treated with rifaximin and were clinically and instrumentally reevaluated 1 and 6 months later. The prevalence of small intestinal bacterial overgrowth was significantly higher in patients than in controls (54.5% vs. 20.0%; P = .01), whereas the prevalence of Helicobacter pylori infection was not (33.3% vs. 26.7%). Compared with patients without any infection, the prevalence of unpredictable fluctuations was significantly higher in patients with both infections (8.3% vs. 87.5%; P = .008). Gastric half‐emptying time was significantly longer in patients than in healthy controls but did not differ in patients based on their infective status. Compared with patients without isolated small intestinal bacterial overgrowth, patients with isolated small intestinal bacterial overgrowth had longer off time daily and more episodes of delayed‐on and no‐on. The eradication of small intestinal bacterial overgrowth resulted in improvement in motor fluctuations without affecting the pharmacokinetics of levodopa. The relapse rate of small intestinal bacterial overgrowth at 6 months was 43%.

Prevalence of Small Intestinal Bacterial Overgrowth in Parkinson's Disease

Parkinsons disease (PD) is associated with gastrointestinal motility abnormalities that could favor the occurrence of small intestinal bacterial overgrowth. The aim of the study was to assess the prevalence of small intestinal bacterial overgrowth in PD patients.

Intestinal permeability in cirrhotic patients with and without spontaneous bacterial peritonitis: is the ring closed?

OBJECTIVES:Impaired intestinal permeability (IP) may have a role in the pathogenesis of ascites and in spontaneous bacterial peritonitis (SBP) in patients with liver cirrhosis (LC). The aim of this study was to assess IP in LC patients with respect to healthy controls.METHODS:IP was evaluated by the 51Cr-ethylenediaminetetraacetic acid (51Cr-EDTA) permeability test in 52 LC patients and in 48 sex- and age-matched controls. The presence of 51Cr-EDTA was also evaluated in ascitic fluid after therapeutic paracentesis in all LC patients with ascites.RESULTS:An altered IP was found in 45% of LC patients compared with 4% of controls (P<0.00001). IP impairment was significantly associated with Child–Pugh status (75% of Child C patients vs. 39% of Child B and 22% of Child A patients), with the presence of ascites (60% in ascitic patients vs. 31% in nonascitic patients), and with a history of SBP (100% of patients with SBP vs. 50% of those without SBP). 51Cr-EDTA was present in all ascitic samples obtained from patients with SBP compared with 22% of patients without SBP.CONCLUSIONS:IP derangement was a common finding in LC, especially in patients with more advanced disease (presence of ascites and history of SBP). The presence of 51Cr-EDTA in ascites in patients with SBP suggests an altered permeability of splancnic vessels and/or peritoneal membranes. Further studies are required to assess 51Cr-EDTA urine and ascite cutoffs to set up SBP preventive strategies.

Small intestinal bacterial overgrowth recurrence after antibiotic therapy

OBJECTIVES:Current treatment for small intestinal bacterial overgrowth (SIBO) is based on courses of broad-spectrum antibiotics. No data concerning SIBO recurrence are available. The aims of the present study were to investigate SIBO recurrence as assessed by glucose breath test (GBT) after antibiotic treatment and conditions associated to SIBO recurrence.METHODS:Eighty consecutive patients affected by SIBO and decontaminated by rifaximin (1,200 mg per day for 1 wk) were enrolled. Diagnosis of SIBO was based on GBT. GBT was reassessed at 3, 6, and 9 months after evidence of GBT normalization. GBT positivity recurrence, predisposing conditions, and gastrointestinal symptoms were evaluated.RESULTS:Ten (10/80, 12.6%), 22 (22/80, 27.5%), and 35 (35/80, 43.7%) patients showed positivity to GBT at 3, 6, and 9 months after successful antibiotic treatment, respectively. At multivariate analysis, older age (OR 1.09, 95% CI 1.02–1.16), history of appendectomy (OR 5.9, 95% CI 1.45–24.19), and chronic use of proton pump inhibitors (PPIs) (OR 3.52, 95% CI 1.07–11.64) were significantly associated to GBT positivity recurrence. All gastrointestinal symptoms significantly increased at 3, 6, and 9 months in patients with evidence of GBT positivity recurrence.CONCLUSIONS:GBT positivity recurrence rate was high after antibiotic treatment. Older age, history of appendectomy, and chronic use of PPIs were associated with GBT positivity recurrence. Patients with evidence of GBT positivity recurrence showed gastrointestinal symptoms relapse thus suggesting SIBO recurrence.

Prevalence of small intestinal bacterial overgrowth in children with irritable bowel syndrome: a case-control study.

OBJECTIVE To assess the prevalence of small intestinal bacterial overgrowth (SIBO) in children affected by irritable bowel syndrome (IBS). STUDY DESIGN Consecutive children affected by IBS according to Rome II criteria (n = 43) were enrolled at the Gemelli Hospital, Catholic University of Rome. The control population (n = 56) consisted of healthy subjects without IBS symptoms, similar to patients for age, sex, and social background. All subjects underwent lactulose/methane breath test (LBT) to assess small intestinal bacterial overgrowth. RESULTS The prevalence of abnormal LBT result was significantly higher in patients with IBS (65%, 28/43) with respect to control subjects (7%, 4/56; OR 3.9, 95% CI 7.3-80.1, P < .00001). Patients with abnormal LBT showed a trend toward a worse visual analog scale score with respect to children with IBS without SIBO, but a significant statistical difference was observed only for bloating. CONCLUSIONS Results from this study suggest a significant epidemiologic association between SIBO and IBS in childhood. Placebo-controlled interventional studies with antibiotics used to treat bacterial overgrowth are warranted to clarify the real impact of the disease on IBS symptoms.

The Role of Methane in Intestinal Diseases

The volume of human intestinal gas is about 200 ml, and it is derived from complex physiological processes including swallowed air, diffusion from bloodstream into the lumen, and particularly intraluminal production by chemical reactions and bacterial fermentation. Gas is continuously removed by eructation, anal evacuation, absorption through the intestinal mucosa, and bacterial consumption. More than 99% of it is composed of hydrogen, oxygen, carbon dioxide, nitrogen, and other odoriferous gases. Methane (CH4) production is detectable in about one third of healthy adult individuals. In the past years, several studies have been focused on CH4 metabolism at the intestinal level and on the putative association between this gas and the pathophysiology of organic and functional bowel disorders. An overview of the present knowledge about the physiology of CH4 metabolism and its role in intestinal diseases is provided in this report.