Small Intestinal Bacterial Overgrowth in Patients with Roux-en-Y Gastric Bypass and One-Anastomosis Gastric Bypass

Prospective Monitoring of Small Intestinal Bacterial Overgrowth After Gastric Bypass: Clinical, Biological, and Gas Chromatographic Aspects

BACKGROUND AND AIMS

Obesity is a predisposing factor for small intestinal bacterial overgrowth (SIBO). The aim of this study was to prospectively evaluate the prevalence of SIBO as well as its clinical, biological, and nutritional aspects before and up to 24 months after a Roux-en-Y gastric bypass (RYGB) surgery.

PATIENTS AND METHODS

Fifty-one patients (mean BMI 46.9 kg/m2, 66.7% women) requesting RYGB were included between 2016 and 2020. Each patient underwent a glucose breath test, a standardized interrogation on functional digestive signs, a dietary survey, a blood test, a fecalogram, and anthropometric data gathering. These investigations were carried out before surgery and at 1, 3, 6, 9, 12, 18, and 24 months after RYGB.

RESULTS

Before surgery, we found a prevalence of 17.6% of SIBO (95% CI = [8.9%; 31.4%]). After RYGB, at the end of 24 months of follow-up, 89.5% of patients developed SIBO. Anal incontinence appeared to be very frequent after surgery, affecting 18.8% of our population 18 months after surgery. We observed positive steatorrhea after surgery with an average of 11.1 g of lipids/24 h despite a significant limitation of dietary lipids (p = 0.0282).

CONCLUSION

Our study corroborates data in the literature on the prevalence of SIBO in severe obesity patients. For the first time, we observed the sudden appearance of SIBO after RYGB, with a correlation between exhaled hydrogen on a breath test and lipid malabsorption on the fecalogram. As a result, these patients develop fatty diarrhea, with frequent fecal incontinence.

The Prevalence of Small Intestinal Bacterial Overgrowth After Roux-en-Y Gastric Bypass (RYGB): a Systematic Review and Meta-analysis

We reviewed the literature on the prevalence of small intestinal bacterial overgrowth (SIBO) after Roux-en-Y gastric bypass (RYGB). Eight studies examining 893 patients were included. The mean age of the patients was 48.11 ± 4.89 years. The mean BMI before surgery and at the time of SIBO diagnosis was 44.57 ± 2.89 kg/m2 and 31.53 ± 2.29 kg/m2, respectively. Moreover, the results showed a 29% and 53% prevalence of SIBO at < 3-year and > 3-year follow-up after RYGB, respectively. Symptoms included abdominal pain, diarrhea, bloating, nausea, vomiting, constipation, soft stool, frequent defecation, flatulence, rumpling, dumping syndrome, and irritable bowel syndrome. SIBO is prevalent after RYGB; digestive symptoms should prompt the consideration of SIBO as a potential etiology. Antibiotic therapy has proven to be therapeutic.

High Prevalence of Small Intestinal Bacterial Overgrowth Syndrome in ICU Patients: An Observational Study

Background: Small intestinal bacterial overgrowth (SIBO), although associated with potentially serious complications, has not been adequately studied in critically ill patients. The primary objective of this study was to assess the prevalence of SIBO in critically ill patients. Secondary outcomes included the assessment of its effect on ventilator-associated pneumonia (VAP), intensive care unit (ICU) length of stay (LOS), and all-cause in-hospital mortality rate. Methods: This prospective observational study was conducted in a mixed medical-surgical ICU. In 52 consecutive ICU patients, a noninvasive modified hydrogen breath test (HBT) with lactulose was employed for SIBO diagnosis. The HBT was conducted at predetermined time intervals (first day of admission; third, fifth, and seventh day of ICU stay). Patients with an abnormal HBT suggesting SIBO on the day of ICU admission were excluded from the study. Participants were classified as either positive or negative based on their HBT on the third, fifth, and/or seventh day. A comparative assessment of demographic data, APACHE II score, incidence of VAP, duration of ICU stay, and all-cause in-hospital mortality was conducted. Multivariate logistic regression analysis was performed to identify the predictive factors for SIBO. Results: The groups were homogeneous in terms of their baseline characteristics. The prevalence of SIBO was 36.5%. The all-cause in-hospital mortality was 34.6%. The presence of SIBO was associated with an increased incidence of VAP (P < .001) and a prolonged ICU length of stay (P < .033). All-cause in-hospital mortality was similar between the groups. Regarding the results of the multivariate logistic regression model, only age was identified as a statistically significant independent predictor of SIBO (OR 1.08, P = .018). Conclusions: The prevalence of SIBO in ICU patients appears to be increased. Both early diagnosis and effective treatment are of utmost importance, especially for critically ill patients since it appears to be associated with VAP and prolonged hospitalization.

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.

Epidemiology of small intestinal bacterial overgrowth

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

The Role of Small Intestinal Bacterial Overgrowth in Obesity and Its Related Diseases

Obesity has become a major public health problem worldwide and its occurrence is increasing globally. Obesity has also been shown to be involved in the occurrence and development of many diseases and pathological conditions, such as nonalcoholic fatty liver disease (NAFLD), type 2 diabetes mellitus (T2DM), insulin resistance (IR). In recent years, gut microbiota has received extensive attention as an important regulatory part involved in host diseases and health status. A growing body of evidence suggests that gut microbiota dysbiosis has a significant adverse effect on the host. Small intestinal bacterial overgrowth (SIBO), a type of intestinal microbial dysbiosis, has been gradually revealed to be associated with obesity and its related diseases. The presence of SIBO may lead to the destruction of intestinal barrier integrity, increased intestinal permeability, increased endotoxin levels, activation of inflammatory responses, and translocation of bacteria from the colon to the small intestine. However, the causal relationship between SIBO and obesity and the specific mechanisms have not been well elucidated. This review discusses the cross-talk between SIBO and obesity and its related diseases, and expounds its potential mechanisms and interventions, which may help to discover new therapeutic targets for obesity and its related diseases and develop treatment options.

Prevalence of Small Intestinal Bacterial Overgrowth Syndrome in Patients with Non-Alcoholic Fatty Liver Disease/Non-Alcoholic Steatohepatitis: A Cross-Sectional Study

INTRODUCTION

Non-alcoholic fatty liver disease (NAFLD) is a multifactorial, wide-spectrum liver disorder. Small intestinal bacterial overgrowth (SIBO) is characterized by an increase in the number and/or type of colonic bacteria in the upper gastrointestinal tract. SIBO, through energy salvage and induction of inflammation, may be a pathophysiological factor for NAFLD development and progression.

AIM/METHODS

Consecutive patients with histological, biochemical, or radiological diagnosis of any stage of NAFLD (non-alcoholic fatty liver [NAFL], non-alcoholic steatohepatitis [NASH], cirrhosis) underwent upper gastrointestinal endoscopy. Duodenal fluid (2cc) was aspirated from the 3rd-4th part of duodenum into sterile containers. SIBO was defined as ≥103 aerobic colony-forming units (CFU)/mL of duodenal aspirate and/or the presence of colonic-type bacteria. Patients without any liver disease undergoing gastroscopy due to gastroesophageal reflux disease (GERD) comprised the healthy control (HC) group. Concentrations (pg/mL) of tumor necrosis factor alpha (TNFα), interleukin (IL)-1β, and IL-6 were also measured in the duodenal fluid. The primary endpoint was to evaluate the prevalence of SIBO in NAFLD patients, while the comparison of SIBO prevalence among NAFLD patients and healthy controls was a secondary endpoint.

RESULTS

We enrolled 125 patients (51 NAFL, 27 NASH, 17 cirrhosis, and 30 HC) aged 54 ± 11.9 years and with a weight of 88.3 ± 19.6 kg (NAFLD vs. HC 90.7 ± 19.1 vs. 80.8 ± 19.6 kg, p = 0.02). Overall, SIBO was diagnosed in 23/125 (18.4%) patients, with Gram-negative bacteria being the predominant species (19/23; 82.6%). SIBO prevalence was higher in the NAFLD cohort compared to HC (22/95; 23.2% vs. 1/30; 3.3%, p = 0.014). Patients with NASH had higher SIBO prevalence (6/27; 22.2%) compared to NAFL individuals (8/51; 15.7%), but this difference did not reach statistical significance (p = 0.11). Patients with NASH-associated cirrhosis had a higher SIBO prevalence compared to patients with NAFL (8/17; 47.1% vs. 8/51; 15.7%, p = 0.02), while SIBO prevalence between patients with NASH-associated cirrhosis and NASH was not statistically different (8/17; 47.1% vs. 6/27; 22.2%, p = 0.11). Mean concentration of TNF-α, IL-1β, and IL-6 did not differ among the different groups.

CONCLUSION

The prevalence of SIBO is significantly higher in a cohort of patients with NAFLD compared to healthy controls. Moreover, SIBO is more prevalent in patients with NASH-associated cirrhosis compared to patients with NAFL.

Association between Gut Dysbiosis and the Occurrence of SIBO, LIBO, SIFO and IMO

Gut microbiota is the aggregate of all microorganisms in the human digestive system. There are 1014 CFU/mL of such microorganisms in the human body, including bacteria, viruses, fungi, archaea and protozoa. The Firmicutes and Bacteroidetes bacteria phyla comprise 90% of the human gut microbiota. The microbiota support the healthy functioning of the human body by helping with digestion (mainly via short-chain fatty acids and amino acids) and producing short-chain fatty acids. In addition, it exhibits many physiological functions, such as forming the intestinal epithelium, intestinal integrity maintenance, the production of vitamins, and protection against pathogens. An altered composition or the number of microorganisms, known as dysbiosis, disrupts the body's homeostasis and can lead to the development of inflammatory bowel disease, irritable bowel syndrome, and metabolic diseases such as diabetes, obesity and allergies. Several types of disruptions to the gut microbiota have been identified: SIBO (Small Intestinal Bacterial Overgrowth), LIBO (Large Intestinal Bacterial Overgrowth), SIFO (Small Intestinal Fungal Overgrowth), and IMO (Intestinal Methanogen Overgrowth). General gastrointestinal problems such as abdominal pain, bloating, gas, diarrhoea and constipation are the main symptoms of dysbiosis. They lead to malabsorption, nutrient deficiencies, anaemia and hypoproteinaemia. Increased lipopolysaccharide (LPS) permeability, stimulating the inflammatory response and resulting in chronic inflammation, has been identified as the leading cause of microbial overgrowth in the gut. The subject literature is extensive but of limited quality. Despite the recent interest in the gut microbiome and its disorders, more clinical research is needed to determine the pathophysiology, effective treatments, and prevention of small and large intestinal microbiota overgrowth. This review was designed to provide an overview of the available literature on intestinal microbial dysbiosis (SIBO, LIBO, SIFO and IMO) and to determine whether it represents a real threat to human health.

Periodontal Therapy in Bariatric Surgery Patients with Periodontitis: Randomized Control Clinical Trial

Background: Bariatric surgery (BS) patients may experience the progression of periodontitis during recovery. We aimed to determine whether non-surgical periodontal therapy before BS improves the periodontal and systemic health parameters after the surgery. Methods: BS candidates with periodontitis were randomized into the test (TG) and control group (CG). One month before BS (pre-BS), patients in the TG (n = 15) received non-surgical periodontal therapy, while patients in the CG (n = 15) received only mechanical plaque removal. Patients were re-examined 3 and 6 months after BS. Differences between the TG and CG in clinical periodontal parameters, systemic health-related serum biomarkers, parameters of obesity, and prevalence of obesity-related diseases were evaluated. Results: From the 30 included patients, 26 were re-examined at 3 months and 20 patients at 6 months. Periodontal parameters bleeding on probing (p = 0.015), periodontal pocket dept (PPD, p = 0.0015), % PPD > 4 mm (p < 0.001), and full-mouth plaque levels (p = 0.002) were lower in the TG than in the CG at 6 months after BS. There is a general improvement in systemic health after BS without significant differences (p > 0.05) between the TG and CG at the 6-month follow-up. The TG shows a tendency for improvement in metabolic syndrome components at the 6-month follow-up compared to pre-BS (p < 0.05). Conclusions: Non-surgical periodontal therapy in periodontitis patients before the BS may improve periodontal health 3 and 6 months after the surgery. The possible benefits of periodontal therapy on the overall health of BS patients should be further explored.