What is SIBO? What are its symptoms, causes, and risk factors? How is SIBO diagnosed and treated? What dietary changes can help manage SIBO? Get the answers to these questions and more in this in-depth article.

Understanding Small Intestinal Bacterial Overgrowth (SIBO)

Small intestinal bacterial overgrowth (SIBO) is a condition where there is an abnormal increase in the number and/or type of bacteria present in the small intestine. Normally, the small intestine contains a relatively small number of bacteria compared to the large intestine. However, in SIBO, the bacterial population in the small intestine becomes excessive, which can lead to a variety of gastrointestinal symptoms and complications.

Symptoms of SIBO

The most common symptoms of SIBO include abdominal pain, bloating, nausea, uncomfortable fullness after eating, loss of appetite, indigestion, excessive gas, diarrhea, and constipation. Some people with SIBO may also experience fatigue, weakness, and unintentional weight loss.

Causes and Risk Factors of SIBO

There are several factors that can contribute to the development of SIBO, including age, anatomical abnormalities in the small intestine, certain medical conditions, and the use of certain medications. Older adults are at a higher risk of SIBO due to decreased gastric acid production and an increased prevalence of diverticulosis. Structural abnormalities in the small intestine, such as those caused by surgery, radiation, or injury, can also disrupt normal intestinal function and lead to SIBO. Additionally, conditions like diabetes, lupus, connective tissue disorders, and inflammatory bowel diseases can predispose individuals to SIBO. Certain medications, such as narcotics, proton pump inhibitors, and antibiotics, can also disturb the delicate balance of gut bacteria and increase the risk of SIBO.

Diagnosing SIBO

Diagnosing SIBO typically involves a combination of medical history, physical examination, and diagnostic tests. Healthcare providers may order imaging tests like X-rays, CT scans, or MRI scans to look for any physical abnormalities in the small intestine. Blood tests can be used to check for anemia or nutrient deficiencies, while stool tests can help assess fat absorption. The two primary diagnostic tests for SIBO are the small intestine aspirate and fluid culture, and the hydrogen breath test.

Treatment of SIBO

The primary treatment for SIBO involves restoring the balance of gut bacteria through the use of antibiotics. Antibiotics commonly prescribed for SIBO include rifaximin, neomycin, amoxicillin-clavulanic acid, ciprofloxacin, metronidazole, and trimethoprim-sulfamethoxazole. The specific antibiotic regimen may depend on the predominant type of bacteria identified in the diagnostic tests. In some cases, a combination of antibiotics may be required. Supplementation with certain nutrients, such as vitamin B12, iron, thiamine, and niacin, may also be necessary to address any nutrient deficiencies caused by SIBO.

Dietary Considerations for SIBO

Dietary modifications can play an important role in the management of SIBO. Avoiding sugary foods and drinks, as well as fiber supplements and liquid medications containing sugar alcohols, may help reduce the growth of harmful bacteria. Some people may also need to eliminate certain foods that seem to trigger their SIBO symptoms, such as lactose-containing products. A low-FODMAP diet, which limits fermentable carbohydrates, has been shown to be effective in managing SIBO symptoms for some individuals.

Preventing and Managing SIBO Complications

If left untreated, SIBO can lead to various complications, including malabsorption of nutrients, anemia, and unintentional weight loss. In some cases, surgery may be necessary to address underlying anatomical issues that are contributing to the development of SIBO. Regular follow-up with a healthcare provider is essential to monitor for any recurrence of SIBO and to ensure proper management of the condition and its associated complications.

In summary, SIBO is a complex condition that requires a comprehensive approach to diagnosis and treatment. By understanding the causes, symptoms, and diagnostic methods, as well as the available treatment options and dietary considerations, individuals with SIBO can work closely with their healthcare providers to effectively manage their condition and improve their overall gastrointestinal health.

Small Intestinal Bacterial Overgrowth (SIBO)

Written by Caitlin Cox

• What Is SIBO?
• SIBO Symptoms
• SIBO Causes and Risk Factors
• SIBO Diagnosis
• SIBO Treatment
• SIBO Diet
• SIBO Complications
• More

Small intestinal bacterial overgrowth (SIBO) is when you have too much bacteria in your small intestine.

Everyone has bacteria in their gut; they play a key part in digestion. But if things get out of balance, problems can happen.

SIBO can be treated, and lifestyle changes may be all it takes.

SIBO may cause:

• Belly pain
• Queasiness
• Bloating
• Uncomfortable fullness after eating
• Loss of appetite
• Indigestion
• Passing a lot of gas
• Diarrhea or constipation
• Fatigue
• Weakness

SIBO usually starts when your small intestine doesn’t move food along the way it should. Bacteria grow and stick around too long. If the “good” bacteria that help you digest food can’t keep up with the harmful bacteria, the “bad” germs can multiply too fast, leading to an imbalance.

Things that can cause SIBO or make it more likely include:

Age. Older adults are at higher risk because they may make less of the gastric acid that breaks down food. They’re also more likely to have diverticulosis.

Anatomy. You may have a small intestine with an unusual shape. Physical differences in your gut can make food move more slowly than it should and allow bacteria to grow. These may happen because of:

• Diverticulosis (pouches in the small intestine)
• Surgical procedures like Roux-en-Y (gastric bypass surgery)
• Scar tissue from radiation or surgery
• Injury to your small intestine
• Unusual passage (fistula) between two parts of your bowel
• A buildup of protein called amyloid in your small intestine
• Blockages in the GI tract

Medical conditions like these can keep your intestines from working the way they should:

• Diabetes
• Lupus
• Connective tissue disorders such as scleroderma
• Weakened immune system because of HIV or an immunoglobulin A deficiency
• Inflammatory bowel diseases like Crohn’s and more rarely, ulcerative colitis

Medicines are sometimes at the root of SIBO. These may include:

• Narcotics
• Drugs that treat irritable bowel syndrome
• Proton pump inhibitors that curb acid in your stomach
• Antibiotics that affect the bacteria in your intestines

Symptoms of SIBO can look like those of many other conditions. If you’ve had symptoms that don’t go away, see a gastroenterologist. This type of doctor specializes in the digestive system.

They’ll probably order tests such as:

• Imaging tests like as X-rays, CT, or MRI to look for physical problems in your intestines
• Blood tests to check for anemia or a lack of vitamins
• Stool tests that look for problems like how much fat your body is absorbing
• Small intestine aspirate and fluid culture. Your doctor passes a long, thin tube called an endoscope through your digestive tract to your small intestine. They take a small sample of the fluid inside and do a lab test called a culture to see what kind of bacteria it has.
• Hydrogen breath test. First, you drink a sugary beverage. Over the next 3 hours, you breathe into a balloon every 15 minutes. This air is tested to see if it has high levels of hydrogen or methane to suggest SIBO.

To treat SIBO, you need to get your gut bacteria back in balance. That should ease your symptoms and help your body absorb more nutrients from your food.

The treatment might depend on the results of your breath test. If your sample had a lot of hydrogen in it, the main treatment is the antibiotic rifaximin (Xifaxan). If your test showed high levels of methane, you’ll probably take rifaximin plus the antibiotic neomycin (Mycifradin).

Other antibiotics that treat SIBO include:

• Amoxicillin-clavulanic acid (Augmentin)
• Ciprofloxacin (Cipro)
• Metronidazole (Flagyl)
• Norfloxacin (Noroxin)
• Trimethoprim-sulfamethoxazole (Bactrim)

You might need to take antibiotics for only a week or two, or for a longer time. Your doctor could also switch among several kinds.

SIBO can make it so your body doesn’t absorb enough of certain nutrients like vitamin B12, iron, thiamine, and niacin. Supplements may help.

Some people need surgery if their SIBO stems from a physical problem with their intestine. If this is the case, see your doctor regularly after the operation to check on your digestive health.

If you don’t have SIBO because of an anatomical problem, a simple step is to cut out sugary foods and drinks. This may be all it takes to feel better.

Other diet changes for SIBO include:

• Quitting foods that seem to make your symptoms worse and waiting 3 days before putting them back on your menu. This way, you’ll know whether a certain food triggers your symptoms.
• Avoiding fiber supplements as well as any liquid medications (such as cough syrup) that use sugar alcohols for flavor.
• Avoiding lactose. If your small intestine is damaged, you might lose the ability to digest lactose, the sugar in milk products.
• A low-FODMAP diet. FODMAP stands for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. FODMAPs are a type of carbohydrate. But not every carb is a FODMAP. A nutritionist or a doctor experienced in nutrition can help you come up with the right plan.
• The elemental diet. This is an eating plan that involves special nutritional formulas instead of typical foods. They’re designed to meet your body’s nutritional needs.
• Prebiotics and probiotics. You can get probiotics in fermented foods like yogurt (look for “live, active cultures” on the label), kefir (a yogurt-based drink), and kimchi (a traditional Korean relish). To get more prebiotics from foods, include lots of fruits, veggies, and whole grains.

If you’re thinking about taking prebiotics or probiotics in supplements, talk with your doctor first to make sure they’re a good choice for you. Foods are always a good first step, since you’ll get lots of other nutrients that are good for you.

Without treatment, SIBO can lead to problems including:

• Lack of vitamins and nutrients
• Electrolyte imbalance
• Diarrhea
• Anemia
• Weight loss
• Weak bones (osteoporosis)
• Kidney stones

Top Picks

Small Intestinal Bacterial Overgrowth (SIBO)

Written by Caitlin Cox

• What Is SIBO?
• SIBO Symptoms
• SIBO Causes and Risk Factors
• SIBO Diagnosis
• SIBO Treatment
• SIBO Diet
• SIBO Complications
• More

Small intestinal bacterial overgrowth (SIBO) is when you have too much bacteria in your small intestine.

Everyone has bacteria in their gut; they play a key part in digestion. But if things get out of balance, problems can happen.

SIBO can be treated, and lifestyle changes may be all it takes.

SIBO may cause:

• Belly pain
• Queasiness
• Bloating
• Uncomfortable fullness after eating
• Loss of appetite
• Indigestion
• Passing a lot of gas
• Diarrhea or constipation
• Fatigue
• Weakness

SIBO usually starts when your small intestine doesn’t move food along the way it should. Bacteria grow and stick around too long. If the “good” bacteria that help you digest food can’t keep up with the harmful bacteria, the “bad” germs can multiply too fast, leading to an imbalance.

Things that can cause SIBO or make it more likely include:

Age. Older adults are at higher risk because they may make less of the gastric acid that breaks down food. They’re also more likely to have diverticulosis.

Anatomy. You may have a small intestine with an unusual shape. Physical differences in your gut can make food move more slowly than it should and allow bacteria to grow. These may happen because of:

• Diverticulosis (pouches in the small intestine)
• Surgical procedures like Roux-en-Y (gastric bypass surgery)
• Scar tissue from radiation or surgery
• Injury to your small intestine
• Unusual passage (fistula) between two parts of your bowel
• A buildup of protein called amyloid in your small intestine
• Blockages in the GI tract

Medical conditions like these can keep your intestines from working the way they should:

• Diabetes
• Lupus
• Connective tissue disorders such as scleroderma
• Weakened immune system because of HIV or an immunoglobulin A deficiency
• Inflammatory bowel diseases like Crohn’s and more rarely, ulcerative colitis

Medicines are sometimes at the root of SIBO. These may include:

• Narcotics
• Drugs that treat irritable bowel syndrome
• Proton pump inhibitors that curb acid in your stomach
• Antibiotics that affect the bacteria in your intestines

Symptoms of SIBO can look like those of many other conditions. If you’ve had symptoms that don’t go away, see a gastroenterologist. This type of doctor specializes in the digestive system.

They’ll probably order tests such as:

• Imaging tests like as X-rays, CT, or MRI to look for physical problems in your intestines
• Blood tests to check for anemia or a lack of vitamins
• Stool tests that look for problems like how much fat your body is absorbing
• Small intestine aspirate and fluid culture. Your doctor passes a long, thin tube called an endoscope through your digestive tract to your small intestine. They take a small sample of the fluid inside and do a lab test called a culture to see what kind of bacteria it has.
• Hydrogen breath test. First, you drink a sugary beverage. Over the next 3 hours, you breathe into a balloon every 15 minutes. This air is tested to see if it has high levels of hydrogen or methane to suggest SIBO.

To treat SIBO, you need to get your gut bacteria back in balance. That should ease your symptoms and help your body absorb more nutrients from your food.

The treatment might depend on the results of your breath test. If your sample had a lot of hydrogen in it, the main treatment is the antibiotic rifaximin (Xifaxan). If your test showed high levels of methane, you’ll probably take rifaximin plus the antibiotic neomycin (Mycifradin).

Other antibiotics that treat SIBO include:

• Amoxicillin-clavulanic acid (Augmentin)
• Ciprofloxacin (Cipro)
• Metronidazole (Flagyl)
• Norfloxacin (Noroxin)
• Trimethoprim-sulfamethoxazole (Bactrim)

You might need to take antibiotics for only a week or two, or for a longer time. Your doctor could also switch among several kinds.

SIBO can make it so your body doesn’t absorb enough of certain nutrients like vitamin B12, iron, thiamine, and niacin. Supplements may help.

Some people need surgery if their SIBO stems from a physical problem with their intestine. If this is the case, see your doctor regularly after the operation to check on your digestive health.

If you don’t have SIBO because of an anatomical problem, a simple step is to cut out sugary foods and drinks. This may be all it takes to feel better.

Other diet changes for SIBO include:

• Quitting foods that seem to make your symptoms worse and waiting 3 days before putting them back on your menu. This way, you’ll know whether a certain food triggers your symptoms.
• Avoiding fiber supplements as well as any liquid medications (such as cough syrup) that use sugar alcohols for flavor.
• Avoiding lactose. If your small intestine is damaged, you might lose the ability to digest lactose, the sugar in milk products.
• A low-FODMAP diet. FODMAP stands for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. FODMAPs are a type of carbohydrate. But not every carb is a FODMAP. A nutritionist or a doctor experienced in nutrition can help you come up with the right plan.
• The elemental diet. This is an eating plan that involves special nutritional formulas instead of typical foods. They’re designed to meet your body’s nutritional needs.
• Prebiotics and probiotics. You can get probiotics in fermented foods like yogurt (look for “live, active cultures” on the label), kefir (a yogurt-based drink), and kimchi (a traditional Korean relish). To get more prebiotics from foods, include lots of fruits, veggies, and whole grains.

If you’re thinking about taking prebiotics or probiotics in supplements, talk with your doctor first to make sure they’re a good choice for you. Foods are always a good first step, since you’ll get lots of other nutrients that are good for you.

Without treatment, SIBO can lead to problems including:

• Lack of vitamins and nutrients
• Electrolyte imbalance
• Diarrhea
• Anemia
• Weight loss
• Weak bones (osteoporosis)
• Kidney stones

Top Picks

The importance of probiotics in the treatment of bacterial overgrowth syndrome » Medvestnik

According to modern concepts, bacterial overgrowth syndrome (SIBO) is understood as an increase in the number of bacteria in the small intestine, leading to the development of symptoms from the gastrointestinal tract (GIT). With SIBO, not only the number increases, but also the composition of microorganisms changes with a shift towards gram-negative bacteria and anaerobes that ferment carbohydrates with the formation of gas ¹ . The diagnostic criterion for SIBO is the content of bacteria ≥10 ⁵ CFU / ml in the aspirate from the small intestine or ≥10 ³ CFU / ml if colonies are formed by colonic bacteria ² .

SIBO may be subclinical or present with symptoms consistent with irritable bowel syndrome (IBS) with associated flatulence, abdominal discomfort, diarrhea, and abdominal pain. As the severity of the process worsens, signs of malabsorption and maldigestion may develop due to the influence of bacteria on enzymatic, metabolic processes in the intestine and sorption ³ .

The etiology of SIBO cannot always be accurately determined, but to one degree or another it is associated with a violation of the endogenous mechanisms of antibacterial control (hydrochloric acid secretion, intestinal motility, intact Bauhin’s valve, intestinal immunoglobulins, bacteriostatic properties of pancreatic secretion and bile) ³ .

Risk factors for the development of SIBO include both structural and anatomical changes in the intestine (diverticula, strictures of the small intestine, consequences of surgical interventions) and functional disorders caused by reduced transit and gastrointestinal motility disorders associated with metabolic disorders, a number of diseases (IBS, liver cirrhosis, renal failure, pancreatitis, inflammatory bowel disease, hypothyroidism, celiac disease, etc.), taking certain medications (antibacterial drugs, proton pump inhibitors, etc.), age of patients (older age) ³ .

According to the literature, SIBO was registered in 78% of patients with IBS ⁴ . Currently, there is no consensus on the existence of a causal relationship between SIBO and IBS in the scientific community. Whether SRK is primary in relation to SIBO or vice versa is still a controversial issue ³ . At the same time, according to the results of a meta-analysis that included 11 studies, abnormal respiratory tests were recorded significantly more often in patients with IBS than in healthy individuals (OR = 4. 46; 95% CI 1.69–11.80) ⁵ .

Currently, various regimens for the treatment of SIBO continue to be evaluated for effectiveness. This can be explained by the fact that this syndrome is often secondary to other nosologies (in particular, IBS), so the treatment is mainly based on the treatment of the underlying disease ² . A key place in the treatment of SIBO is the use of antimicrobial drugs (for example, such as rifaximin, amoxicillin, ciprofloxacin, metronidazole, tetracycline, etc.) with an empirical approach to the choice of a specific drug, dosage and duration of administration. Taking into account the fact that in SIBO and IBS there is a change in the composition of the microbiota, in addition to basic therapy, it is advisable to use drugs aimed at restoring the microbiota – probiotics ² .

Bifiform drug has a balanced composition, contains two strains of bacteria – Enterococcus faecium ENCfa-68 at a dose of at least 1×10 ⁷ CFU and Bifidobacterium longum BB-46 at a dose of at least 1×10 ⁷ CFU ⁶ . Double layered enteric capsule protects beneficial bacteria from the aggressive environment of the stomach ⁸ .

In the study of I.N. Ruchkina et al. (2013) evaluated the effectiveness of the drug “Bifiform” in patients with post-infectious IBS (pIBS). The study included 138 patients with iBS ⁸ , while 59.4% of patients were diagnosed with secondary lactase deficiency (SLN), which in all cases was accompanied by SIBO in the lumen of the small intestine and was confirmed by the results of a respiratory hydrogen test (101±37 10 ^-6 at the norm – 6). After a 14-day course of the drug “Bifiform” (“Bifiform” + basic therapy), eubiosis in the lumen of the small intestine was restored in 70.8% of patients, which was manifested by a decrease in the severity of SIBO (86.9±40.9 10 ⁻⁶ before treatment 17.4±6.6 10 ⁻⁶ after treatment; p7.

According to the instructions for medical use, when taking the drug “Bifiform” in the recommended doses according to the established indications, no adverse reactions were detected. The drug is approved for use in adults and children from the age of 2 years ⁸ .

Learn more

References:

1. Pimentel M, Saad RJ, Long MD et al. ACG clinical guideline: Small intestinal bacterial overgrowth. Am J Gastroenterol. 2020;115:165-78. https://doi.org/10.14309/ajg.0000000000000501.

2. Ivashkin K.V., Grechishnikova V.R., Reshetova M.S., Ivashkin V.T. Relationship between irritable bowel syndrome and bacterial overgrowth syndrome: a bacterial hypothesis at the basis of functional disease. Russian journal of gastroenterology, hepatology, coloproctology. 2021;31(1):54-63. https://doi.org/10.22416/1382-4376-2021-31-1-54-63.
3. Maev I.V., Kucheryavy Yu.A., Andreev D.N. Small Intestine Bacterial Overgrowth Syndrome: Clinical Significance, Diagnostic Criteria, and Therapeutic Tactics. Infectious diseases: news, opinions, training. 2016;3.
4. Pimentel M, Chow E, Lin HC. Eradication of small intestinal bacterial overgrowth reduces symptoms in irritable bowel syndrome. Am J Gastroenterol. 2000;95:3503-6.
5. Shah ED, Basseri RJ, Chong K, Pimentel M. Abnormal breath testing in IBS: A meta-analysis. Dig Dis Sci. 2010;55(9):2441-9.
6. Kornienko E.A., Mazankova L.N., Gorelov A.V. The use of probiotics in pediatrics: analysis of therapeutic and prophylactic effects from the standpoint of evidence-based medicine. Attending doctor. 2015;9.
7. Ruchkina I.N. The role of the microflora of the small intestine in the development of secondary lactase deficiency and the possibility of its treatment with probiotics. Therapeutic archive. 2013;2:21-6.
8. Instructions for the medical use of the drug “Bifiform” RU P N013677/01 dated 06/08/2011.

The material is intended for employees of the healthcare system

GlaxoSmithKline Healthcare JSC, Russian Federation, 123112, Moscow, Presnenskaya nab., 10, room III, room 9, floor 6. Tel. +7 (495) 777-98-50
The trademark is owned or used by the GlaxoSmithKline Group of Companies.
PM-EN-BIF-22-00009

Partner material: GlaxoSmithKline Healthcare

Modern approaches to the management of patients with bacterial overgrowth syndrome

Author:
CM. Tkach, Dr. med. D., Professor, Ukrainian Scientific and Practical Center for Endocrine Surgery, Transplantation of Endocrine Organs and Tissues of the Ministry of Health of Ukraine, Kyiv,

03/27/2021

Adapted from the latest 2020 American College of Gastroenterology Clinical Guideline

Bacterial overgrowth syndrome (SIBO) as a specific medical phenomenon has been known for many decades. Although its definition is still debatable, the fundamental point is that, normally, microbial colonization in the small intestine should be significantly less than in the large intestine. With SIBO, the normal balance of the intestinal microbiota (IM) is significantly disturbed, the number of bacteria in the small intestine increases (more than 10 ³ colony forming units (CFU) per 1 ml), which is the cause of gastroenterological symptoms. SIBO is typically formed by an increase in predominantly Gram-negative aerobic and anaerobic bacteria that ferment dietary carbohydrates, produce intestinal gases, and cause bloating [1].

After establishing the critical role of CM in human health in the late 1990s. the number of studies on the clinical role of SIBO has increased significantly [2]. A large number of scientific articles have appeared on the association of SIBO with irritable bowel syndrome (IBS) [3,4], inflammatory bowel disease [5], scleroderma and multiple sclerosis [6], motor disorders [7,8], cirrhosis [9], non-alcoholic fatty liver disease [10], postgastrectomy syndrome [11], and many other diseases and conditions.

Currently, there is a need to establish the strength and quality of evidence-based studies in the field of SIBO, to revise the criteria for its diagnosis and to establish optimal methods of treatment [12]. This is what the new clinical guidelines of the American College of Gastroenterology (ACG) published this year are devoted to [13]. The GRADE approach and the principles of best clinical practice were applied during the development of this ACG guideline [12]. Below are the main recommendations and key provisions of the new ACG clinical guidelines regarding the management of patients with SIBO (Tables 1, 2).

Definition

SIBO can be defined as a clinical syndrome with gastrointestinal (GI) symptoms caused by an excess of bacteria in the small intestine. This definition assumes that bacterial overgrowth (IBG) in the small intestine can be measured and is accompanied by specific GI signs and symptoms. For example, abnormal fermentation of nutrients that are normally completely absorbed in the small intestine can lead to excess gas production and bloating.

Measurement of the number of bacteria in the small intestine was initially carried out by inoculating aspirates from the proximal small intestine and obtaining a culture [14]. However, culture-derived threshold quantitative IBR values ​​have long been a subject of controversy among experts in the field and have remained controversial in the scientific literature. The latest North American consensus concluded that the diagnosis of IBD requires the presence of 10 ³ CFU/ml in aspirate from the duodenum or proximal small intestine [14].

An alternative method for diagnosing SIBO is the quantitative measurement of hydrogen in exhaled air after ingestion of a fixed amount of carbohydrate substrates such as glucose or lactulose [15, 16]. Although breath tests (RTs) are widely used, they are indirect methods for assessing IBD in the small intestine. Regarding the threshold diagnostic values ​​of TD for the detection of IBD and the technique for their implementation, the scientific literature also continues to discuss. Taking into account the most recent data, it is recommended that a rise in the level of hydrogen in the exhaled air of more than 20 ppm above the baseline for 9 years be used as a diagnostic criterion for SIBO.0 minutes after oral administration of 75 g of glucose or 10 mg of lactulose [13].

Clinical signs and/or symptoms of SIBO result from nutrient malabsorption, impaired intestinal permeability, inflammation, and/or immune activation that result from abnormal bacterial fermentation in the small intestine [17]. The main symptoms of SIBO are nausea, bloating, flatulence, abdominal distension, abdominal pain, diarrhea and/or constipation, which occur in about 70% of patients. Less common may be steatorrhea, weight loss, iron deficiency and anemia, deficiency of fat-soluble vitamins (D and B ₁₂ ) and/or inflammation of the small intestine mucosa [17, 18]. These symptoms are usually associated with extraordinary causes of SIBO, such as post-surgical blind loop syndrome or scleroderma [19]. Some patients have unmotivated fatigue and deterioration in concentration [20]. However, there is not a single symptom pathognomonic for SIBO. Symptoms of SIBO are often “masked” behind diagnoses such as IBS, functional diarrhea, functional dyspepsia, or bloating. The symptoms of these diseases may be part of SIBO, but there are also many risk factors that contribute to the development of SIBO. For example, in a patient with chronic pancreatitis, it is difficult to determine whether diarrhea is due to exocrine pancreatic insufficiency or concomitant SIBO. Similarly, in Crohn’s disease, it is difficult to determine whether abdominal pain, bloating, and diarrhea are due to active inflammation, bile acid malabsorption, postoperative strictures, or whether they are associated with SIBO.

Diagnostics

Breath tests

Quantitative measurement of hydrogen and/or methane in exhaled air is a relatively inexpensive, non-invasive, easy to perform, and widely used method for diagnosing SIBO. The principle of the test is that human cells are not capable of producing hydrogen or methane. Therefore, if these gases are detected in the exhaled air, there must be other sources of their production, such as the fermentation of carbohydrates by intestinal bacteria. Therefore, when we orally ingest carbohydrate substrates such as glucose and lactulose, they are quickly fermented by intestinal bacteria, producing hydrogen that is absorbed into the bloodstream and can be detected in exhaled air. The more bacteria in the small intestine, the more hydrogen is produced and, accordingly, the higher the rates of DT. Methanogenic archaea (prokaryotes lacking a DNA-containing nucleus), on the contrary, use hydrogen as a substrate for methane production [16, 21]. If an increase in hydrogen concentration in breath samples indirectly indicates SIBO, then, according to the North American consensus, a 10 ppm increase in methane levels suggests overgrowth of methane-producing archaea. Therefore, a new term has now been proposed – “Methanogenic Overgrowth Syndrome” (SIMR) [13]. Prior to DT, the patient should avoid taking antibiotics for 1 month, prokinetics or laxatives for 1 week. The day before DT, fermented food is excluded, and the study is carried out on an empty stomach 8-12 hours after eating. During DT, one should not smoke and move actively [16].

Regardless of the nomenclature, if the change in the concentration of hydrogen or methane does not exceed the threshold values, this indicates a negative result. When lactulose is used as a substrate, there are usually two peaks in the increase in hydrogen concentration (the first is associated with IBD in the small intestine, and the second reflects bacterial fermentation in the large intestine). According to the provisions of the new consensus, the second peak is not taken into account for the diagnosis of IBD, but the first should be observed during the first 90 minutes after taking 10 g of lactulose. According to a systematic review by Khoshini et al. [14], the sensitivity of the lactulose hydrogen test in the diagnosis of SIBO ranges from 31 to 68%, and the specificity is from 44 to 100%, while the sensitivity of the glucose test ranges from 20 to 93%, and the specificity is from 30 to 86%, when comparing similar indicators of the culture test.

Small bowel aspiration and culture

Small bowel aspirate and culture are considered the gold standard for diagnosing SIBO. Unfortunately, the standardization of small bowel sampling techniques is not well developed, culture results may vary depending on the location of the aspirate catheter and its quantity. It is also quite difficult to observe aseptic conditions when taking the material. At present, the technique of obtaining aspirate from the descending duodenum (3-5 ml) during upper endoscopy is practiced, which allows minimizing cross-contamination of the material with bacterial contents of the stomach and oral cavity. Previously, the threshold positive result for the diagnosis of SIBO was considered an indicator of 10 ⁵ cfu/ml and above. However, recent results have shown that this indicator is overestimated, and for the diagnosis of SIBO it is enough to get an indicator above 10 ³ CFU / ml [13, 15].

Currently, there is a growing number of studies using duodenal sequencing of 16S-ribosomal RNA to diagnose SIBO. At the same time, in patients with IBS and concomitant SIBO, an increase in the ratio of Escherichia/Shigella (p=0.005), the number of Aeromonas (p=0.051) and Pseudomonas , as well as a decrease in the number of Acinetobacter (p=0.024), Citrobacter (p=0.031) and Microvirgula (p=0.036) [22, 23].

New technicians

Since the available DTs have a relatively low sensitivity and specificity, the search for new standard methods for diagnosing SIBO continues, in particular, the creation of a unique capsule technology capable of measuring the concentration of hydrogen and CO 9 in vivo 0129 2 [24, 25].

Practical advice

SIBO Diagnostics

Recommendation 1. For the diagnosis of SIBO in patients with IBS, hydrogen DT (glucose or lactulose) is recommended

Conditional recommendation, very low level of evidence.

IBS is a fairly common disease in which the presence of SIBO is most often determined. Although the incidence of SIBO in IBS is a matter of debate, it is thought to be as high as 78% [26]. These data are based both on the results of molecular genetic testing of patients with IBS [23, 27, 28], and on the results of the TARGET 1, 2 and 3 studies confirming the effectiveness of the nonabsorbable selective intestinal antibiotic rifaximin in IBS [29]. The high efficacy of rifaximin allowed the US Food and Drug Administration (FDA) to officially recommend it for the treatment of patients with IBS with diarrhea. A relatively recent study showed that positive results of lactulose DT predict the response of patients with IBS to rifaximin. In fact, 76% of patients with positive lactulose DT were identified as responders who demonstrated eradication of SIBO and clinical improvement after a course of rifaximin (1200 mg/day for 14 days) [30].

Recommendation 2. Hydrogen DT (glucose, lactulose) are recommended for the diagnosis of SIBO in patients with suspected motor impairment.

Conditional recommendation, very low level of evidence.

Recommendation 3. Hydrogen DT (glucose, lactulose) for the diagnosis of SIBO is recommended for patients with symptoms (abdominal pain, flatulence, bloating and/or diarrhea) after abdominal surgery.

Conditional recommendation, very low level of evidence.

Other conditions associated with SIBO

There are quite a few mechanisms that ensure relatively low bacterial contamination of the small intestine (Table 3). Failure or breakthrough of one or more of these mechanisms can lead to IBD in the small intestine. Table 4 presents the main conditions traditionally associated with SIBO.

SIBO may not only be associated with these conditions, but may also be a direct cause of malabsorption, vitamin deficiencies, and other problems. It should be said that many of the conditions associated with SIBO are empirically determined. High-level evidence-based research on the diagnosis and treatment of SIBO is clearly insufficient and should be continued.

Gastric acidity and proton pump inhibitors

Recommendation 4. DT is not recommended for asymptomatic patients taking proton pump inhibitors (PPIs).

Conditional recommendation, very low level of evidence.

Gastric acidity plays a critical role as a deterrent to the development of SIBO. Patients with hypochlorhydria or achlorhydria due to autoimmune gastritis or after resection/gastrectomy have an increased risk of developing SIBO [11, 31]. PPIs, which are the main drugs for the treatment of acid-dependent pathology, can give incomprehensible GI symptoms. Spiegel et al. described an association between PPI use and the development of SIBO, as did many other studies that showed a high risk of SIBO in PPI users [32-34]. According to a recent meta-analysis 19studies covering more than 7,000 patients, it is assumed that the risk of developing SIBO in PPI users is increased by 3 times [35]. However, the same meta-analysis indicates that it is not possible to accurately determine whether the dose, duration of treatment, and type of PPI contribute to the development of SIBO, since high-quality evidence-based studies are lacking [35].

Methane production and excess methanogenic growth

Recommendation 5. In symptomatic patients with constipation, detection of methane-producing microorganisms using methane DT is recommended.

Conditional recommendation, very low level of evidence.

One of the clinical applications of DT is intriguing and concerns the role of methane. Several studies and 1 meta-analysis have shown that positive methane DT is associated with constipation (odds ratio (OR) 3.51, confidence interval (CI) 2.00-6.16) and that the level of methane in exhaled air correlates with the severity of constipation [36 -39]. Methane is produced not by bacteria, but by archaea, nuclear-free prokaryotic organisms that represent a form of life distinct from bacteria and eukaryotes. In humans, excess methane production is carried out mainly Methanobrevibacter smithii [40]. Excess methane production is not caused by IBD, but by archaea overgrowth. Therefore, in these cases, it is advisable to use not the term SIBO, but “methane SIBO” or “Methanogenic Overgrowth Syndrome” (SIMR).

Treatment

Antibiotics

Recommendation 6. Patients with SIBO who present with symptoms are recommended to be treated with antibiotics for its eradication and resolution of symptoms.

Conditional recommendation, very low level of evidence.

The use of antibiotics is a cornerstone in the treatment of SIBO. Moreover, the practice of empirical use of antibiotics in the presence of risk factors and clinical signs suspicious of SIBO has long been established. Unfortunately, the negative effects of antibiotic therapy are on the rise, including the development of antibiotic resistance, side effects, and an increase in opportunistic infections such as Clostridioides difficile . Therefore, before prescribing antibiotics, it is desirable to establish the presence of SIBO.

One of the most effective antibacterial drugs for SIBO is the selective non-absorbable intestinal antibiotic rifaximin-α. A meta-analysis of 32 clinical studies showed its efficacy and safety in SIBO [41]. The analysis included 7 randomized clinical trials, 24 cohort studies, and 1 crossover study covering a total of 1,221 patients with SIBO. Despite the high heterogeneity of studies (doses and duration of treatment varied significantly), the average overall efficacy of rifaximin-α in the eradication of IBD was 70. 8% (CI 61.4-78.2), and minor side effects were observed only in 4.6% cases. In another 2 studies, the effectiveness of rifaximin-α in the eradication of IBD at a dose of 600 to 1200 mg per day for 7 days was 76-78% [42, 43]. Rifaximin-α is currently one of the main drugs for the treatment of IBS without constipation, especially in combination with SIBO. Several RCTs and meta-analyses have shown that rifaximin-α significantly reduced the symptoms of IBS and was therefore approved by the FDA in 2015 for the treatment of IBS with diarrhea. This decision is based on data from 3 phase III clinical trials – TARGET 1, TARGET 2 and TARGET 3 – involving more than 3,000 patients. Patients treated with rifaximin-α 1200 mg/day for 2 weeks experienced significant improvement in all symptoms of IBS compared with placebo (52% vs 44%; p=0.03) and a reduction in bloating (46% vs 40%; p= 0.04). During 12 weeks of follow-up, the number of patients with relief of symptoms and bloating after taking rifaximin-α increased to 62 and 59%, respectively (p<0. 05 compared to placebo). In each study, rifaximin-α was well tolerated with an overall incidence of side effects no greater than placebo. Repeated courses of rifaximin-α treatment in IBS patients with diarrhea were as safe and effective as the initial one, since its effect on the normal intestinal microflora is limited to the period of use and it does not cause the development of resistance. In addition, in recent years, it has been established that rifaximin has its own probiotic properties, in particular, it increases the amount of useful Lactobacillus . Therefore, recently rifaximin-α is not even considered as a selective intestinal antibiotic, but as an intestinal eubiotic.

Other studies of varying quality have examined the efficacy of amoxicillin-clavulanate, chlortetracycline, ciprofloxacin, doxycycline, metronidazole, neomycin, norfloxacin, rifaximin, and trimethoprim-sulfamethaxazole in SIBO (Table 5) [44–46].

There are also isolated studies on the effectiveness of antibiotics for the treatment of SIRT. Monotherapy with neomycin or rifaximin for 10 days in SIMR was effective in an average of 30% of cases, while the combined use of both drugs increased the effectiveness of treatment up to 87% [47].

Diet

There are several likely mechanisms by which a particular diet may be beneficial in SIBO. First of all, it is recommended to reduce the consumption of fermented foods, alcohol, sugar and sweeteners, as well as such a prebiotic as inulin. In general, the diet for SIBO should be similar to the diet for IBS. The most effective diet is limited to FODMAPs (fermentable oligo-, di- and monosaccharides and polyols) [48].

Probiotics

Studies on the efficacy of probiotics in SIBO are few and of low quality. According to a meta-analysis, the ability of some probiotics to lead to a decrease in hydrogen production in SIBO was recorded (OR 1.61; CI 1.19-2.17) [49].

Fecal microbiota transplantation

Studies on the effectiveness of fecal microbiota transplantation in SIBO are rare and do not yet allow any conclusions to be drawn regarding the appropriateness of its implementation in the described pathology [50].

Thus, the above data will optimize approaches to the diagnosis and treatment of patients with SIBO. The main provisions of the new ACG clinical guidelines, based on evidence-based medicine, will generally help practitioners improve their knowledge of the management of patients with SIBO and improve the results of treatment of this pathology.

The list of references is in the editorial office.

Thematic issue “Gastroenterology. Hepatology. Coloproctology” № 1 (59) 2021

• Number:
• Thematic issue “Gastroenterology. Hepatology. Coloproctology» № 1 (59) 2021

06/20/2023

Gastroenterology NPZP and gastrosafety: myth or reality?

12 May for the support of the Ministry of Health of Ukraine, the National Medical University named after. O.O. Bogomolets (m. Kiev), National University of Health Protection of Ukraine named after. P.L. Shupika (city of Kiev) held a symposium “Management of pain and stress disorders”, in the program of which Bulo presented a wide range of additional ideas related to the control of pain and stress. Of particular interest is the associate professor of the Department of Clinical Pharmacy and Clinical Pharmacology of the Vinnitsa National Medical University named after. M.I. Pirogov, Candidate of Medical Sciences Oleksandri Oleksiivna Klekot “NPZP and gastrosafety: myth or reality?”….

06/20/2023

Gastroenterology The role of bioregulatory correction of autonomic disorders in chronic pancreatitis: practical aspects

bathing. The ailment is accompanied by various symptoms and disorders, among which vegetative and immune systems are found to be conductive. The current reach of medicine gives wide possibilities for bioregulatory corrective (BRK) therapy for the management of vegetative and immune disorders in CP. One of the options is the use of RBK-drugs, which are complexly injected into the nervous and immune system….

06/07/2023

GastroenterologyNew in the management of patients with diseases of the organs of the gastrointestinal tract

At the herbal interdisciplinary consultation “Traveler of diseases of the organs of the gastrointestinal tract. Why should we emphasize respect?”, attributions to the nutrition of diagnostics and the treatment of pathology of the intestines and chewing michur (ZHM) ….

06/02/2023

GastroenterologyTherapy and family medicineOrganization of nutritional support for patients with chronic pancreatitis ovoї zoloza in subjects from genetic, related and other risk factors, for example, hypertriglyceridemia.