Bacteroides uniformis

Bacteroides uniformis is a Gram-negative, obligate anaerobic bacterium that plays a significant role in the human gut microbiota, particularly within the Bacteroidetes phylum. 

These bacteria are crucial for maintaining gut homeostasis by breaking down complex polysaccharides into short-chain fatty acids (SCFAs) like acetate and propionate, which are essential for gut health, immune modulation, and energy metabolism. 

The presence and abundance of Bacteroides spp. in the gut are influenced by factors such as diet, host genetics, and environmental exposures, and they interact with other gut bacteria to regulate immune responses and nutrient metabolism. 

B. uniformis has been noted for its potential benefits in weight management, glucose metabolism, and reducing symptoms of colitis, making it a promising target for therapeutic interventions aimed at improving gut health and preventing metabolic and inflammatory diseases.

Overview of Bacteroides spp. [1., 9., 14., 19., 21., 23., 25., 27.] 

Bacteroides spp., members of the Bacteroidetes phylum, are significant components of the human gut microbiota, crucial for maintaining gut homeostasis. 

This phylum, constituting about 30% of the human gut microbiota, includes several genera such as Bacteroides, Prevotella, and Porphyromonas. 

The proportion of Bacteroidetes varies based on population, geography, age, and diet.

Characteristics and Taxonomy

Bacteroides spp. are gram-negative, non-spore forming, anaerobic, rod-shaped bacteria. Approximately 24 species have been identified, with Bacteroides fragilis and Bacteroides thetaiotaomicron being the most studied. 

These bacteria thrive in anaerobic conditions, utilizing complex polysaccharides for energy through fermentation. 

They possess unique genetic and metabolic features that enable efficient degradation of dietary fibers and carbohydrates, producing short-chain fatty acids (SCFAs) and other metabolites that impact host physiology.

The Bacteroides genus uses a Type VI secretion system (T4SS) to maintain competitive advantage in the gut. [4.] 

The T4SS in Bacteroides helps maintain competition and balance in the human gut by releasing toxins that target other bacteria, enabling these bacteria to outcompete others and stabilize the gut ecosystem, often through the transfer of these systems via mobile genetic elements among neighboring strains. [4.] 

Role in the Human Microbiome [9., 20., 27.]

Bacteroides spp. are key members of the human gut microbiome, significantly contributing to the microbial community in the colon. 

Their presence and abundance are influenced by diet, host genetics, and environmental exposures. 

Bacteroides spp. interact with other commensal bacteria and host cells, participating in complex microbial networks that regulate immune responses, nutrient metabolism, and intestinal barrier function.

Bacteroidetes, primarily found in the distal gut, possess a similar function of harvesting energy from diet through the fermentation of indigestible polysaccharides, producing short-chain fatty acids (SCFAs). [30.] 

Metabolic Contributions

In adults, Bacteroides and other Bacteroidetes produce SCFAs such as acetate, propionate, and butyrate from the fermentation of undigested dietary polysaccharides. SCFAs play crucial roles in gut health, glucose homeostasis, and lipid metabolism. 

‍Bacteroides and Prevotella are major contributors to SCFA production, especially propionate. These bacteria adapt flexibly to the gut's nutritional environment, using a wide range of dietary polysaccharides and proteins.

Despite their diversity, Bacteroidetes share a high capacity for polysaccharide utilization, aided by numerous carbohydrate-active enzymes (CAZYmes). Their metabolic flexibility allows them to switch between different substrates based on availability and competition within the gut ecosystem. [8.]

Diet and Bacteroidetes:

Diet significantly influences Bacteroidetes levels. 

Short-term diets rich in animal products increase Bacteroides, while long-term high fiber diets also support their dominance. [8.] 

Overnutrition decreases Bacteroidetes, affecting energy harvest efficiency. Conversely, undernutrition and fasting can either increase or deplete Bacteroidetes levels, depending on the conditions. [8.] 

Bacteroidetes and Metabolic Diseases:

Studies show varied associations between Bacteroidetes and type 2 diabetes. The relative abundance of Bacteroidetes can affect glucose metabolism differently in individuals, influenced by diet and other factors. 

Gnotobiotic animal studies show specific Bacteroidetes species can have different effects on host metabolism. Daily dosing with Bacteroides cultures improved glucose tolerance and insulin sensitivity in mice, suggesting microbial metabolites as potential metabolic effectors.

However, high Bacteroides have also been associated with impaired glucose tolerance. Bacteroides species' levels correlate with glucose responses post-meal, emphasizing the importance of dietary context. [8.] 

In one study, continuous blood glucose monitoring in 800 participants showed that the relative abundance of Bacteroidetes in stool was associated with a poor postprandial glucose response. [8.] 

However, within the phylum, many Bacteroides species correlated positively with a healthy postprandial glucose response when participants consumed diets optimized to their individual microbiota, dietary habits, and other factors. [8.] 

Overall, the effects of Bacteroidetes on glucose metabolism can vary significantly depending on dietary context and on the relative levels of Bacteroides subspecies. [8.] However, overall a healthy amount of Bacteroides seems to be beneficial for human metabolic health. [8., 11.]

Health Implications

Modulating Bacteroides metabolism through dietary interventions holds potential for restoring gut microbiota balance and promoting metabolic health. 

Imbalances in the composition of the gut microbiota, including alterations in Bacteroides spp. abundance, have been associated with numerous disease states. 

‍Bacteroidetes have been associated with metabolic disease, although the association between Bacteroidetes and metabolic diseases like obesity and type 2 diabetes is complex and context-dependent. [8.] 

Bacteroides has shown potential in preventing and treating non-alcoholic fatty liver disease (NAFLD) by modulating gut health.  [30.] 

By reducing liver inflammation, mitigating hepatic steatosis, and enhancing intestinal barrier function, they contribute to metabolic regulation, improve insulin resistance, and balance cytokines. 

While the mechanisms are not fully understood, Bacteroides’ ability to influence lipid metabolism and gut barrier integrity positions them as promising candidates for NAFLD therapy, although more clinical research is needed to confirm their efficacy.

What is Bacteroides uniformis?

Bacteroides uniformis is a species of Gram-negative, obligate anaerobic bacteria isolated from human feces. 

It is part of the Bacteroides genus, which is a significant component of the human gut microbiota, contributing to various beneficial functions like short-chain fatty acid production, maintenance of a healthy gut lining, and immune modulation in the digestive tract. 

Bacteroides uniformis, along with other species like B. vulgatus, B. caccae, and B. thetaiotaomicron, is considered part of the core microbiota due to its high relative abundance in the gut. [23.] 

Bacteroides species play a crucial role in producing short-chain fatty acids (SCFAs), particularly acetate and propionate. 

These SCFAs have important health benefits, such as blocking the transportation of toxins between the gut lumen and blood and inducing apoptosis in human colon carcinoma cells, potentially preventing tumor formation. [23.] 

Additionally, Bacteroides species are involved in the synthesis of vitamin K, which is essential for various bodily functions​​. [23.] 

Isoflavone Metabolism and Absorption

Bacteroides uniformis is identified as a degrader of isoflavones. [15.] 

Understanding which bacteria, such as Bacteroides uniformis, contribute to isoflavone degradation can help tailor dietary recommendations. For instance, individuals with gut microbiota that efficiently degrade isoflavones may benefit less from soy-based isoflavone supplements intended for their estrogen-like effects.

Weight Regulation, Metabolism and Obesity

Bacteroidetes, including B. uniformis, are efficient at fermenting indigestible polysaccharides into short-chain fatty acids (SCFAs), contributing up to 10% of daily caloric intake in fiber-rich diets. This fermentation process is vital for energy balance and weight management. [8.] 

Studies involving germ-free mice transplanted with human gut microbiota have shown that microbiomes with higher proportions of Bacteroidetes, including B. uniformis, are linked to lower fat gain compared to those dominated by Firmicutes. [8.] 

Additionally, daily dosing of conventionally raised mice with B. uniformis cultures has been shown to improve glucose tolerance and insulin sensitivity, indicating a beneficial role in metabolic health. [8.] 

In obese individuals, weight loss has been associated with an increase in Bacteroidetes, suggesting a dynamic relationship between gut microbiota composition and body weight. [8.] 

Overfeeding studies have indicated that Bacteroidetes abundance decreases with excessive caloric intake, correlating with increased energy harvest and contributing to weight gain. Conversely, weight loss interventions and caloric restriction can increase Bacteroidetes levels. [8.]

In a study conducted on diet-induced obese mice, the combination of B. uniformis and wheat bran extract (WBE), a type of fiber, was found to be the most effective in reducing weight gain and adiposity compared to either treatment alone. [23.] 

This combination also improved whole-body glucose disposal, increased the production of butyrate, and enhanced immune defense by restoring the proportion of intraepithelial lymphocytes and type-3 innate lymphoid cells in the intestinal epithelium. [23.] 

Furthermore, this intervention reduced liver inflammation and altered IL22 signaling, highlighting its potential in managing obesity and associated metabolic disorders​​​​. [23.] 

Ulcerative Colitis and Irritable Bowel Disease [28.] 

Bacteroides uniformis can significantly help with colitis, which occurs commonly in inflammatory bowel disease (IBD). 

In a study with mice, treatment with B. uniformis reduced colitis symptoms such as weight loss and colon inflammation. It also improved the health of the colon by increasing beneficial bacteria like Bifidobacterium and Lactobacillus vaginalis, while reducing harmful bacteria such as Escherichia-Shigella. 

B. uniformis altered bile acid levels in the colon, which helped suppress inflammatory immune cells called TH17. 

This change in bile acids and gut bacteria led to lower inflammation and better overall gut health. 

The findings suggest Bu could be a promising treatment for colitis and other gut-related issues.

Chronic Kidney Disease and Cardiovascular Disease

Despite its health benefits, B. uniformis has also been associated with worse outcomes in both chronic kidney disease and cardiovascular disease. [21.] 

This increased presence of B. uniformis, along with other Bacteroides species such as B. ovatus and B. caccae, suggests a shift in the gut microbiome composition associated with CKD. These bacteria are known to produce uremic toxins, which can exacerbate CKD and contribute to complications such as cardiovascular disease. [21.] 

Other members of the Bacteroides genus have also been associated with the production of toxins, including B. fragilis and B. caccae. 

Laboratory Testing for Bacteroides uniformis

Test Type, Sample Collection and Preparation

Bacteroides uniformis levels are assessed in stool samples.  Stool samples may be collected from the comfort of home.  

Testing may require avoidance of certain medications and/or supplements including probiotics prior to sample collection.  It is important to consult with the ordering provider for full test preparation instructions.  

Interpretation of Test Results

Optimal Levels of Bacteroides uniformis

It is important to consult with the laboratory company used for test interpretation.  Bacteroides levels are typically assessed by species, although some lesser-known species, such as Bacteroides uniformis, may be reported as part of Bacteroides spp.  

One lab company provides the following reference range for Bacteroides spp. levels alongside Prevotella spp. (another member of the Bacteroidetes phylum), and reports this on a scale from -3 (low prevalence of these organisms) to +3 (high prevalence of these organisms).  [17.]

Clinical Implications of High Bacteroides 

High levels of Bacteroides in the gut microbiome are generally associated with a healthy state and favorable metabolic outcomes. 

A high relative abundance of Bacteroides compared to other phyla like Firmicutes is considered essential for maintaining gut health, biodiversity, and homeostasis of metabolism, immune function, and colonization resistance.  

Bacteroidetes, the phylum of which Bacteroides are a part, are considered a "keystone taxon" in the gut microbiome, and their depletion can lead to detrimental shifts in the microbial community structure.  [12., 23.]

Several studies have found an association between high Bacteroidetes levels and a lean phenotype or healthy weight.  A higher Bacteroidetes/Firmicutes ratio was associated with a lower body mass index (BMI).  [8., 11.]

Conversely, a lower abundance of Bacteroidetes has been observed in obese individuals compared to lean individuals.  [8.] 

High levels of Bacteroidetes species like Bacteroides fragilis and B. thetaiotaomicron are considered beneficial as commensals, fermenting polysaccharides to produce short-chain fatty acids that serve as an energy source for the host. [23.] 

They also contribute to bile acid metabolism and provide colonization resistance against pathogens like Clostridioides difficile.  [23.]

However, elevated levels of Bacteroides in the setting of digestive symptoms or pathology warrants further assessment for bacterial strains such as enterotoxin-producing B. fragilis or B. caccae, which have been associated with digestive pathology in certain settings.  

Low Bacteroides Abundance  [1., 10., 11., 18.]

Lower levels of Bacteroides have been associated with inflammatory bowel diseases (IBD) like ulcerative colitis, where specific Bacteroides species exhibit significantly lower abundance compared to healthy controls.

The loss of these species is suggested to result from disease exacerbation and may serve as potential biomarkers for disease activity.

Low Bacteroides levels may disrupt microbial community dynamics, favoring the overgrowth of potentially harmful bacteria and diminishing the beneficial effects of Bacteroides-mediated functions, such as the fermentation of dietary fibers and production of short-chain fatty acids (SCFAs).  [5.] 

Therefore, maintaining a relatively high abundance of Bacteroides in the gut microbiome is generally considered a favorable state, associated with better metabolic health, a lean phenotype, and a lower risk of inflammatory conditions like IBD. 

Low Bacteroides along with high Firmicutes has also been associated with metabolic disorders. [8., 11.] 

Monitoring Bacteroides levels may have clinical significance in assessing gut health, disease risk, and potential therapeutic interventions aimed at restoring a balanced microbiome.

Natural Ways to Optimize Microbiome Health [7.] 

A healthy diet and lifestyle are foundational for microbiome health.  

Diet and Nutrition

• Consume Diverse Foods: increase the variety of fruits, vegetables, whole grains, nuts, seeds, and legumes to promote microbial diversity.

• High-Fiber Diet: focus on fiber-rich foods to support the growth of beneficial bacteria.

• Fermented Foods: include yogurt, kefir, sauerkraut, kimchi, and other fermented foods to introduce probiotics.

• Polyphenol-Rich Foods: consume foods high in polyphenols such as berries, green tea, dark chocolate, and red wine to stimulate beneficial bacteria growth.

• Prebiotics: incorporate prebiotic-rich foods like garlic, onions, asparagus, and bananas to nourish beneficial bacteria.

Lifestyle

• Regular Exercise: engage in consistent physical activity to enhance gut microbiota diversity and composition.

• Stress Management: practice stress-reducing activities such as yoga, meditation, and mindfulness to prevent microbiota dysbiosis.

Medications and Supplements

• Probiotics: consider probiotic supplements to increase beneficial bacteria in the gut.

• Avoid Unnecessary Antibiotics: use antibiotics only when necessary to avoid disrupting the gut microbiome.

Environmental Factors

• Limit Artificial Sweeteners: avoid artificial sweeteners that can negatively affect gut microbiota.

• Healthy Sleep Patterns: maintain regular sleep patterns to support a balanced gut microbiome.

Hygiene Practices

• Avoid Over-Sanitization: limit the use of antibacterial soaps and sanitizers to maintain a healthy microbiota balance.

Bacteroides uniformis Related Biomarkers

While Bacteroides uniformis is a valuable biomarker on its own, its diagnostic and prognostic utility can be significantly enhanced when used alongside other biomarkers. 

Firmicutes/Bacteroidetes Ratio [8., 9., 11.]

The Firmicutes/Bacteroidetes ratio is an important marker of gut microbiota composition and health. 

Bacteroides uniformis belongs to the Bacteroidetes phylum, and changes in its levels can affect this ratio. A higher Firmicutes/Bacteroidetes ratio has been associated with obesity and metabolic disorders, while a lower ratio is often seen in individuals with inflammatory bowel disease (IBD). 

However, a lower ratio also indicates an increased abundance of Bacteroides, which is also associated with gastrointestinal health and metabolic benefits.  

By assessing the Firmicutes/Bacteroidetes ratio, clinicians can gain a more comprehensive understanding of the gut microbiome's state and its potential impact on health. 

This integrated approach can help in diagnosing metabolic and inflammatory conditions and tailoring interventions to restore microbial balance.

Short-Chain Fatty Acids (SCFAs)

Short-chain fatty acids (SCFAs) such as acetate, propionate, and butyrate, are products of microbial fermentation of dietary fibers in the gut. Bacteroides uniformis and other Bacteroides species play a key role in the production of SCFAs through the degradation of polysaccharides. 

Measuring SCFA levels in conjunction with Bacteroides uniformis provides insights into the functional activity of the gut microbiome and its impact on host health. 

SCFAs have anti-inflammatory properties and contribute to gut barrier integrity and energy metabolism. Alterations in SCFA levels can indicate dysbiosis and have been linked to conditions such as IBD, IBS, and metabolic syndrome. 

By integrating SCFA measurements with Bacteroides uniformis levels, clinicians can better assess gut health and develop targeted nutritional or probiotic therapies.

Inflammatory Markers

Inflammatory markers, such as C-reactive protein (CRP) and interleukins (e.g., IL-6), are commonly used to assess systemic inflammation and immune responses. 

Since the gut microbiome plays a critical role in modulating inflammation, measuring inflammatory markers alongside Bacteroides uniformis levels can provide valuable information about the interaction between the gut microbiota and the immune system. 

FAQ: Understanding Bacteroides uniformis

Bacteroides uniformis is a species of bacteria that plays a significant role in the human gut microbiome. This FAQ section addresses common questions about Bacteroides uniformis, its significance, its impact on health, and potential treatments and dietary considerations.

What is Bacteroides uniformis?

Bacteroides uniformis is a species of Gram-negative, anaerobic bacteria that belongs to the Bacteroides genus. These bacteria are commonly found in the human gastrointestinal tract and play an important role in the digestion of complex carbohydrates and the maintenance of gut health.

Where are Bacteroides uniformis Found?

Bacteroides uniformis is predominantly found in the distal part of the human gastrointestinal tract. 

They are an integral part of the gut microbiome, contributing to the breakdown of dietary fibers and other complex carbohydrates.

Are Bacteroides uniformis Good or Bad?

Bacteroides uniformis is generally considered beneficial as it helps in the digestion of complex carbohydrates and supports gut health. However, like other gut bacteria, an imbalance or overgrowth can potentially contribute to health issues. 

Under normal circumstances, Bacteroides uniformis plays a positive role in maintaining a healthy gut microbiome.

What Are the Benefits of Bacteroides uniformis?

The benefits of Bacteroides uniformis include aiding in the digestion of complex carbohydrates, producing beneficial short-chain fatty acids, supporting the gut barrier function, and helping maintain a balanced gut microbiome.  It may also support optimal metabolic health in humans.  

How is Bacteroides uniformis Detected?

Bacteroides uniformis can be detected using microbiological and molecular techniques such as stool culture, 16S rRNA gene sequencing, and metagenomic analysis. These methods allow for the identification and quantification of Bacteroides uniformis in the gut microbiome.

What Foods Support Bacteroides uniformis?

To support the growth of Bacteroides uniformis, include foods rich in dietary fiber such as:

• Fruits (e.g., apples, berries)

• Vegetables (e.g., broccoli, carrots)

• Whole grains (e.g., oats, quinoa)

• Legumes (e.g., beans, lentils) These foods provide the necessary substrates for Bacteroides uniformis to thrive and perform their beneficial functions in the gut.

What is the Treatment For an Overgrowth of Bacteroides uniformis?

Treatment for an overgrowth of Bacteroides uniformis typically involves restoring a healthy balance in the gut microbiome. This can be achieved through:

• Antibiotics: Used selectively to reduce the overgrowth of Bacteroides uniformis.

• Probiotics and prebiotics: To support the growth of beneficial bacteria.

• Dietary changes: Including more fiber-rich foods to promote a balanced microbiome.

• Fecal microbiota transplantation (FMT): In severe cases of dysbiosis, FMT may be considered to restore a healthy balance of gut bacteria.

Can Bacteroides uniformis Cause Infections?

Bacteroides uniformis is generally beneficial, but it can cause infections if it translocates to sterile areas of the body or if there is an imbalance in the gut microbiome. 

Infections are rare but can occur, especially in individuals with weakened immune systems or underlying health conditions.

How does Bacteroides uniformis Interact with Other Gut Bacteria?

Bacteroides uniformis interacts with other gut bacteria through competitive and cooperative relationships. 

These interactions help maintain a balanced gut microbiome, where beneficial bacteria support each other's growth and function while keeping pathogenic bacteria in check.

When Should I Consult a Healthcare Provider About My Gut Microbiome?

You should consult a healthcare provider if you experience persistent digestive issues such as abdominal pain, bloating, diarrhea, or constipation. 

A healthcare provider can evaluate your symptoms, potentially recommend microbiome testing, and suggest appropriate treatments or dietary changes to improve gut health.

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