Bacteroides vulgatus

Bacteroides vulgatus, a prominent member of the Bacteroidetes phylum, plays a significant role in the human gut microbiota, contributing to the degradation of complex carbohydrates and production of short-chain fatty acids (SCFAs) crucial for gut health. 

Research has shown that B. vulgatus is involved in maintaining gut homeostasis and integrity, influencing metabolic processes and immune responses. 

Dysbiosis, or an imbalance in gut microbiota, has been linked to various conditions including Autism Spectrum Disorders (ASD), where elevated levels of B. vulgatus correlate with autism severity. This bacterium can produce SCFAs like propionic acid, which, in high concentrations, may be neurotoxic and influence behavior. 

However, B. vulgatus has demonstrated potential in ameliorating lipid metabolic disorders and reducing inflammation, highlighting its therapeutic potential for metabolic health and gut-related diseases.

Overview of Bacteroides spp. [2., 10., 15., 20., 24., 26., 28.] 

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. [5.] 

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. [5.]

Role in the Human Microbiome [10., 20., 28.]

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). [31.]

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. [9.] 

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. [9.] 

Overnutrition decreases Bacteroidetes, affecting energy harvest efficiency. Conversely, undernutrition and fasting can either increase or deplete Bacteroidetes levels, depending on the conditions. [9.] 

‍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. [9.] 

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. [9.] 

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. [9.] 

Overall, the effects of Bacteroidetes on glucose metabolism can vary significantly depending on dietary context and on the relative levels of Bacteroides subspecies. [9.] However, overall a healthy amount of Bacteroides seems to be beneficial for human metabolic health. [9.,12.]

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. [9.]

Bacteroides has shown potential in preventing and treating non-alcoholic fatty liver disease (NAFLD) by modulating gut health.  [31.] 

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 Vulgatus?

As a member of the Bacteroides genus, Bacteroides vulgatus is a key player in the degradation of complex carbohydrates and the production of short-chain fatty acids (SCFAs).  Bacteroides vulgatus also helps maintain gut homeostasis and gut lining integrity, and influences metabolic processes.

Metabolism, Hyperlipidemia, and Weight Loss

Bacteroides vulgatus has demonstrated significant potential in ameliorating lipid metabolic disorders and modulating gut microbiota composition, particularly in the context of obesity and hyperlipidemia. 

Studies involving hyperlipidemic rats fed a high-fat diet showed that supplementation with B. vulgatus Bv46 significantly reduced body weight gain, improved lipid profiles, and lowered inflammation markers. [29.]

This bacterium also promoted the loss of fecal bile acids (BAs) and increased the fecal pool of short-chain fatty acids (SCFAs), notably propionate and butyrate, which are known to have beneficial metabolic effects. [29.] 

The presence of B. vulgatus in the gut led to a compositional shift in the gut microbiota, decreasing the Firmicutes to Bacteroidetes ratio, a marker often associated with a healthy weight and metabolism. [28., 29.] 

Additionally, B. vulgatus Bv46 was shown to enhance the abundance of beneficial gut bacteria such as Bacteroides and Parabacteroides, further supporting its role in improving gut health and metabolic function.

Mechanistically, B. vulgatus Bv46 modulated several metabolic pathways, including bile acid biosynthesis and fatty acid metabolism, contributing to better lipid homeostasis and reduced cholesterol levels. 

The bacterium's bile salt hydrolase (BSH) activity facilitated the deconjugation of bile acids, promoting their excretion and reducing cholesterol reabsorption. This was complemented by upregulation of genes involved in cholesterol and bile acid metabolism, such as CYP7A1 and CYP27A1, in the liver.

Another study highlighted the potential role of B. vulgatus in weight loss, suggesting that B. vulgatus might have a cross-feeding relationship with Akkermansia muciniphila, another bacterium known to positively influence obesity reduction. [21., 22.] 

Intestinal Inflammation and Inflammatory Diseases

B. vulgatus may help to ameliorate inflammation and promote gut healing in the setting of intestinal inflammation.  [21.] 

It does this through various pathways including anti-inflammatory cytokine production, anti-inflammatory short chain fatty acid production, and altering the gut microbiome to favor the presenceof other anti-inflammatory bacterial strains. [21.] 

Autism and Autism-Spectrum Disorders [33.] 

Research indicates that the gut microbiota, including Bacteroides vulgatus, may significantly influence Autism Spectrum Disorders (ASD). 

Studies show that children with ASD often exhibit gastrointestinal issues and dysbiosis, an imbalance in their gut microbial communities. Elevated levels of Bacteroides vulgatus and Desulfovibrio in these children correlate with autism severity. [33.]

These microbial imbalances can affect neurodevelopment and behavior through the microbiota-gut-brain (MGB) axis. 

B. vulgatus, for example, may contribute to the production of short-chain fatty acids (SCFAs) like propionic acid, which in high concentrations can be neurotoxic and influence behaviors in animal models. [33.] 

Additionally, dysbiosis in ASD is linked to altered immune responses, including increased inflammatory cytokines, further impacting neurological symptoms. 

Intervention studies, such as fecal microbiota transplants (FMT), have shown promise in altering gut microbiota and improving ASD symptoms, highlighting the potential therapeutic role of targeting specific gut microbes like B. vulgatus. [33.] 

Bone Health [11.]

Bacteroides vulgatus (B. vulgatus) is a gut bacterium that has been found to negatively impact bone mineral density (BMD). 

Research involving peri- and post-menopausal women revealed a negative association between B. vulgatus and BMD, a finding validated in both Chinese and American populations. [11.] 

B. vulgatus affects bone health by influencing the levels of valeric acid (VA), a metabolite positively associated with BMD. 

Studies showed that feeding B. vulgatus to ovariectomized mice increased bone resorption and worsened bone structure, while VA administration had the opposite effect. VA inhibits pro-inflammatory proteins and promotes anti-inflammatory responses, enhancing bone formation and reducing bone breakdown.  

Colorectal Cancer

High levels of B. vulgatus may be associated with an increased risk of colorectal cancer. [1.] 

Alongside Bacteroides fragilis and Fusobacterium nucleatum, B. vulgatus was identified as part of the altered microbiota composition that may influence CRC progression. 

While the abundance of B. vulgatus varied among the patients, it was implicated in contributing to the breakdown of the gut's colonic wall, potentially aiding in CRC development. [1.] 

Laboratory Testing for Bacteroides vulgatus

Test Type, Sample Collection and Preparation

Bacteroides vulgatus 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 vulgatus

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 vulgatus, 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.  [13., 24.]

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).  [9., 12.]

Conversely, a lower abundance of Bacteroidetes has been observed in obese individuals compared to lean individuals.  [9.] 

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. [24.] 

They also contribute to bile acid metabolism and provide colonization resistance against pathogens like Clostridioides difficile.  [24.]

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  [2., 12., 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).  [6.] 

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. [9., 12..] 

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 [8.] 

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 vulgatus Related Biomarkers

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

Firmicutes/Bacteroidetes Ratio [9., 10., 12.]

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

Bacteroides vulgatus 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 vulgatus 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 vulgatus 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 vulgatus 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 vulgatus levels can provide valuable information about the interaction between the gut microbiota and the immune system. 

FAQ: Understanding Bacteroides vulgatus

Bacteroides vulgatus is a significant species within the human gut microbiome, playing crucial roles in digestion and overall health. This FAQ section addresses common questions about Bacteroides vulgatus, its significance, and potential treatments related to its presence in the gut.

What is Bacteroides vulgatus?

Bacteroides vulgatus is a species of Gram-negative, anaerobic bacteria that belongs to the Bacteroides genus. These bacteria are commonly found in the human gastrointestinal tract, where they aid in the digestion of complex carbohydrates and contribute to maintaining gut health.

What Role Does Bacteroides vulgatus Play in the Gut Microbiome?

Bacteroides vulgatus helps break down and ferment complex carbohydrates that the human body cannot digest on its own. 

This process produces short-chain fatty acids and other metabolites that support gut health and overall metabolic functions.

How is Bacteroides vulgatus Detected?

Bacteroides vulgatus 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 vulgatus in the gut microbiome.

What Are the Benefits of Bacteroides vulgatus?

The benefits of Bacteroides vulgatus 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.

Can Bacteroides vulgatus Be Harmful?

Under normal circumstances, Bacteroides vulgatus is beneficial and contributes to a healthy gut. However, an imbalance in the gut microbiome (dysbiosis) can sometimes lead to overgrowth of certain bacteria, including Bacteroides vulgatus.

What is the Treatment for an Overgrowth of Bacteroides vulgatus?

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

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

• 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.

How does Bacteroides vulgatus Interact With Other Gut Bacteria?

Bacteroides vulgatus 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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