Eradication of intestinal bacterial overgrowth as a treatment method for functional dyspepsia

Functional dyspepsia (FD) is one of the most common gastrointestinal functional diseases, occurring in an average of 10 % of the adult population. Recently, much attention is being paid to the infectious factor in FD pathophysiology. In addition to H. pylori infection and acute gastrointestinal infections, consideration is given to the syndrome of intestinal bacterial overgrowth (SIBO), in which the number of bacteria in the small intestine increases significantly. Objective — to establish the SIBO prevalence in patients with different FD subtypes and to establish the clinical and microbiological efficacy of rifaximin‑a (Alpha Normix®) at this pathology. Materials and methods. To refine the SIBO prevalence, 118 patients with FD were examined in three gastroenterological centers, including 45 men, 73 women aged 22 to 45 years (mean age — 35 ± 10 years). The control group consisted of 30 clinically healthy people with the mean age 33 ± 12 years. The diagnosis of FD and establishment of its subtype was performed according to Rome IV criteria. All patients underwent upper endoscopy with biopsy and H. pylori testing, which did not show any structural abnormalities. To diagnose SIBO, all patients underwent H2‑breath test with lactulose (H2‑LBT). All patients, depending on the FD subtype, received basic therapy with either a proton pump inhibitor (Omeprazole 20 mg once a day) at FD with epigastric pain syndrome (EPS) (group 1, n = 37), or prokinetic (Itopride in a dose of 50 mg three times a day) at FD with postprandial distress syndrome (PDS) (group 2, n = 36) for two weeks. Patients with positive H2‑LBT result, which predicted SIBO presence, were administered monotherapy with rifaximin‑a (Alpha Normix®) in a dose of 1200 mg/day for 10 days. The effectiveness of the treatment was assessed after 2 and 4 weeks based on the dynamics of the scores of SAGIS (Structured Assessment of Gastrointestinal Symptom) scale. Results. According to the positive H2‑LBT results, SIBO presence was recorded in 45 of 118 patients with FD (38.1 %) and 2 (6.6 %) subjects from the control group. Positive H2‑LBT result was significantly more often recorded in patients with FD‑PDS (45.4 %) compared with patients with FD‑EPS (28.8 %, p < 0.01) and all patients with FD (38.1 %). Moreover, SIBO was significantly more common in patients with postinfectious FD (50 % of patients, p < 0.01). The use of rifaximin in a dose of 1200 mg/day for 10 days was accompanied by the clinical improvement in 28 of 45 patients (62.2 %) after 4 weeks of treatment. The clinical efficacy of rifaximin in FD patients on the SAGIS scale did not differ significantly from the efficacy of PPIs and prokinetics used in FD‑EPS and FD‑PDS, respectively. After 4 weeks, in 36 of 45 patients, repeated H2‑LBT was negative, which indirectly indicated the SIBO eradication and high antibacterial efficacy of rifaximin. Rifaximin treatment was safe, and minor side effects were observed in only 3 patients (6.6 %). Conclusions. SIBO is quite often associated with FD and is observed in more than every third patient. In patients with FD‑PDS, SIBO was found significantly more often than in patients with FD‑EPS, which emphasizes the important role of slowing gastric emptying in the development of SIBO. Also, SIBO is significantly more common in patients with postinfectious FD, which emphasizes the important role of the intestinal microbiome in maintaining the stability of the structural and functional state of the gastrointestinal tract. The obtained data allow to consider SIBO as a possible pathogenetic factor of FD, at least in some patients. This requires timely diagnosis and correction of SIBO in patients with FD, in particular with the use of rifaximin‑a.

Association of small intestinal bacterial overgrowth with nonalcoholic fatty liver disease in children: A meta-analysis

It has been suggested that small intestinal bacterial overgrowth (SIBO) could cause nonalcoholic fatty liver disease (NAFLD), but this association was not examined in children by meta-analysis. This meta-analysis aimed to determine the association between SIBO and NAFLD in children. The electronic databases PubMed, Embase, and Cochrane Library were searched for studies published before April 22, 2021. The outcome was the association between SIBO and NAFLD. Three studies and 205 children were included. All three studies reported the association between SIBO and NAFLD. Children with SIBO were more likely to have NAFLD (odds ratio = 5.27, 95% confidence interval (CI): 1.66–16.68, P<0.001; I2 = 63.5%, Pheterogeneity = 0.065). When directly pooling the reported relative risks (RR) from two studies, children with NAFLD had an over 2-fold increased relative risk of developing SIBO (RR = 2.17, 05%CI: 1.66–2.82, P<0.001; I2 = 0.0%, Pheterogeneity = 0.837). This meta-analysis reports a possible association between SIBO and NAFLD in children.

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.

Prevalence of Small Intestinal Bacterial Overgrowth (SIBO) In Type 2 Diabetes Mellitus: A Systematic Review

Purpose: Gastrointestinal symptoms affect 50-70% of diabetic patients, resulting in a microbiota composition imbalance. Autonomic neuropathy is irreversible, resulting in diabetic enteropathy and sometimes even small intestine bacterial overgrowth (SIBO). SIBO can result in bile acid deconjugation, diarrhea, steatorrhea, vitamin and micronutrient malabsorption, weight loss, mucosal injury, bacterial translocation, and worsened intestinal motility. Carbohydrate malabsorption is related to the pathogenesis of diabetic macrovascular complications. The goal of this study is to find out how prevalent SIBO is in type 2 diabetes patients. Methods: "Small intestinal bacterial overgrowth," "small bowel bacterial overgrowth," “SIBO,” "type 2 diabetes mellitus," and "type 2 DM," are the keywords used. We searched Proquest, CINAHL, SCOPUS, ScienceDirect, PubMed/MEDLINE, and manual searches through world diabetes associations such as ADA, EASD, EFSD, IDF, FASEB, and PERKENI using the keywords. We use the Joanna Briggs Institute (JBI) Critical Appraisal Checklist for bias risk assessment, and for data analysis, we use STATA 16. Results: Six articles covered 1072 type 2 diabetes patients in clinics and hospitals. With a minimum score of 7.42% and a maximum value of 53.85%, 95% CI 9.97-38.86, and an I2 of 97.17%, the pooled prevalence was 24.39% SD 15.31. HbA1c levels were higher (p=0.02) in type 2 DM patients with SIBO, and blood insulin levels were lower (p=0.001) in type 2 DM patients with SIBO. Each study was pretty varied, and there was evidence of publication bias. Assessment of findings based on GRADE is moderate. Conclusion: According to this study, SIBO is present in 24.39% of type 2 diabetes patients. SIBO conditions exacerbate the morbidity of patients with type 2 diabetes, as indicated by lower insulin levels and a higher HbA1c. In type 2 diabetes patients, a hydrogen breath test (HBT) is recommended to be performed regularly, especially in those who have had DM for more than 5 years.