Alistipes onderdonkii

Alistipes onderdonkii, a gram-negative, anaerobic bacterium, is a notable member of the Alistipes genus within the Bacteroidetes phylum, primarily isolated from human feces. 

Named after microbiologist Andrew B. Onderdonk, this species is recognized for its significant role in the gut microbiome, producing metabolites like succinic, acetic, and propionic acids. 

Alistipes onderdonkii exhibits both immunomodulatory and anti-inflammatory properties, which can influence conditions such as obesity, inflammatory bowel disease, and cancer. 

Its presence in the gut is associated with metabolic processes and inflammation, highlighting its dual roles in health and disease. 

The clinical identification of Alistipes onderdonkii is challenging due to limitations in mass spectrometry methods, but its impact on human health underscores the importance of further research into its functions and implications.

What is Alistipes onderdonkii?

Alistipes is a gram negative, anaerobic genus of bacteria isolated from clinical samples, primarily from the gut microbiome. This genus, belonging to the Bacteroidetes phylum, includes 13 known species.  [9.] 

It is a butyrate-producing species with both pro- and anti-inflammatory effects.  [8.]  It also produces acetate and propionate.  [9.]

Most members of the Alistipes spp. are bile-resistant, making them tolerant to colonizing areas of the distal ileum where most bile reabsorption happens.  [2., 9.]  This may have clinical relevance regarding relative abundance or absence of Alistipes spp. in certain conditions involving bile resorption.  [9.] 

Alistipes is associated with the metabolism of plant cell wall polysaccharides and resistant starch, compounds found in fruits and vegetables.  [16.]  

‍Alistipes species, excluding A. inops, produce sulfonolipids—a unique class of sphingolipids that are associated with anti-inflammatory benefits.  [15.] 

Alistipes spp. was discovered in 2003 after being isolated from samples from children with appendicitis.  [11.]  It’s recognized as a normal part of the human microbiome, although it can also be associated with various health conditions, showing both protective and pathogenic roles.  [14.] 

Clinical Isolation and Identification

Alistipes species, such as A. finegoldii, A. putredinis, and A. onderdonkii, have been isolated from patients with appendicitis, abscesses, and other conditions.  [10.] 

However, their clinical identification is often underrepresented due to limitations in current mass spectrometry (MS-TOF) methods.  [10.] 

Alistipes spp. Pathogenic and Protective Roles in Human Health  [10.] 

Alistipes shows contrasting roles in health:

Protective Effects 

Alistipes spp. demonstrates protective roles against liver fibrosis, colitis, cancer immunotherapy, and cardiovascular disease.

Pathogenic Effects

Alistipes spp. has been linked to colorectal cancer and mental health issues like depression.

What is Alistipes Onderdonkii?

Alistipes onderdonkii is the most commonly extracted member of the Alistipes species from human feces.  [1.]

This species was named to honor Andrew B. Onderdonk, a microbiologist known for his contributions to intestinal and anaerobic microbiology.  [10.] 

This bacterium is catalase-negative and nitrogen-reductase negative, with succinic acid as the major metabolic end-product, along with minor amounts of acetic and propionic acid. [10.] 

Alistipes onderdonkii has demonstrated immunomodulatory and anti-inflammatory effects, which occur at least in part by reducing TNF production.  [6.] 

Alistipes Onderdonkii Role in Human Health and Disease

Alistipes onderdonkii has been associated with various health conditions, particularly those related to the gut microbiome and inflammatory processes.

Obesity

Studies have shown a correlation between increased levels of Alistipes onderdonkii, very closely related species including Alistipes obesi, and obesity. [13.]

The bacterium may contribute to metabolic dysregulation and low-grade inflammation observed in obesity, especially in the setting of bacterial imbalance.  [10.] 

Inflammatory Bowel Disease [10.] 

Alistipes onderdonkii has been implicated in inflammatory bowel diseases (IBD) such as Crohn's disease and ulcerative colitis. Inflammatory bowel disease is related to microbial dysbiosis. 

Research shows both protective and pathogenic roles for Alistipes onderdonkii in inflammatory bowel disease.   

Lower levels of Alistipes may contribute to the severity of conditions like IBD and colitis. Alistipes spp. are known to produce sulfonolipids with anti-inflammatory properties, potentially beneficial for gut health. [10., 15.]

Cancer Progression

Emerging evidence suggests that Alistipes onderdonkii may affect the development and progression of cancer. For example, its levels are often increased in individuals with colorectal cancer, potentially influencing tumor growth and immune response. [10.] 

However, decreased levels of Alistipes onderdonkii have also been associated with progression of pancreatic cancer. [3.]

Laboratory Testing for Alistipes onderdonkii Levels

Test Type, Sample Collection and Preparation

Alistipes onderdonkii 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 Alistipes onderdonkii

Optimal levels are generally determined by assessing the balance of healthy vs. unhealthy microbiota.  It is important to consult with the laboratory company used for test interpretation. 

One company reports Alistipes onderdonkii levels on a reference range from -3 to +3.  -3 may mean decreased levels of Alistipes spp., while +3 may mean that the individual is tending towards an overgrowth of Alistipes spp.  [12.]

Overall, a moderate amount of Alistipes onderdonkii as part of a healthy microbiome is likely ideal for health.  

Clinical Significance of High Alistipes onderdonkii Levels

The significance of high Alistipes onderdonkii levels is complex.  

Some studies suggest that Alistipes may have protective effects against certain conditions, including colitis, liver fibrosis, and cardiovascular disease.  [10.] 

Additionally, Alistipes produces short-chain fatty acids (SCFAs) like butyrate, acetate and propionate, which have healthy anti-inflammatory properties.  [8., 10., 15.] 

However, possible detrimental effects have also been associated with elevated Alistipes levels:

Elevated levels of Alistipes have been linked to colorectal cancer (CRC).  [10.] 

Increased abundance of some Alistipes species has been positively correlated with systolic blood pressure in patients with hypertension, suggesting a potential role in gut barrier dysfunction and inflammation.  [4.]

Alistipes has also been implicated in various conditions including depression, stress, and chronic fatigue.  [3., 9., 10.]

Additionally, while some research suggests a protective role in cardiovascular diseases, other studies have found a decrease in Alistipes species in patients with atrial fibrillation.  [10.] 

Ultimately, it's important to note that the evidence for Alistipes' role in various conditions is often contradictory, with some associations being protective and others potentially pathogenic.  Therefore, a moderate amount of Alistipes in the setting of appropriate microbiological diversity is likely optimal.  

Clinical Significance of Low Alistipes onderdonkii Levels

The clinical significance of low Alistipes levels also shows a complex clinical picture. 

Low levels of Alistipes spp. have positive and negative connotations for health; results should be correlated with an individual’s health history and current symptoms.  

Low levels of Alistipes have been correlated with: 

Liver Health and Diseases [10., 16.] 

Reduced levels of Alistipes spp. are associated with liver cirrhosis, non-alcoholic steatohepatitis (NASH), and non-alcoholic fatty liver disease (NAFLD). As liver cirrhosis progresses, there is a notable decrease in A. indistinctus. 

In NASH patients, a significant reduction in A. finegoldii is observed, while in NAFLD patients with significant fibrosis, A. onderdonkii levels markedly decrease.

Cardiovascular Health and Diseases [10., 17.] 

Patients with atrial fibrillation show a significant decrease in Alistipes species, which might be linked to an increase in other bacteria like Streptococcus.

Increased levels of A. finegoldii and A. indistinctus correlate with higher systolic blood pressure, suggesting that lower levels may be protective against hypertension.

Gut Health and Inflammation [10.] 

Lower levels of Alistipes, particularly A. finegoldii, may contribute to the severity of conditions like colitis. Alistipes spp. are known to produce sulfonolipids with anti-inflammatory properties, potentially beneficial for gut health.

Cancer (CRC) [10.]

Reduced levels of Alistipes are linked to a decreased risk of colorectal cancer. Alistipes spp. can play a role in modulating the tumor microenvironment, aiding in cancer immunotherapy.

Depression and Chronic Fatigue [10.] 

Low levels of Alistipes spp. are associated with better mental health outcomes. Higher levels are linked to stress, chronic fatigue syndrome, and depression due to their potential to decrease serotonin availability by utilizing tryptophan for indole production.

Biomarkers Related to Alistipes Onderdonkii

In addition to Alistipes spp., other members of the gut microbiome and associated metabolites have been studied as potential biomarkers for various health conditions.

Other Gut Bacteria as Biomarkers

Several other bacterial genera within the gut microbiome have been investigated as potential biomarkers, including Bacteroides, Prevotella, Faecalibacterium, and Akkermansia. 

Changes in the abundance and composition of these bacteria have been linked to conditions such as inflammatory bowel diseases, obesity, and metabolic disorders.  [1.] 

Metabolites and Compounds Associated with Alistipes onderdonkii

Alistipes spp. and other gut bacteria are involved in the production and metabolism of various compounds, some of which may serve as biomarkers. 

For example, short-chain fatty acids (SCFAs), such as acetate, butyrate and propionate, are produced by gut bacteria and have been associated with gut health and inflammation.  [8., 10.] 

In addition to Alistipes onderdonkii, several other biomarkers related to the gut microbiome and intestinal health are being investigated for their potential clinical utility.

Fecal Calprotectin

Fecal calprotectin, a protein released by neutrophils during intestinal inflammation, is a well-established biomarker for inflammatory bowel diseases. Its levels correlate with the degree of intestinal inflammation and can aid in disease monitoring and treatment decisions.

Intestinal Inflammation Markers

Various inflammatory markers such as C-reactive protein (CRP), interleukins, and tumor necrosis factor-alpha (TNF-α), have been studied in the context of intestinal disorders and may provide complementary information to gut microbiome-based biomarkers.

FAQ: Alistipes onderdonkii

What is Alistipes onderdonkii?

Alistipes onderdonkii is a species of bacteria that belongs to the Bacteroidetes phylum. It is a part of the human gut microbiota and is found in the gastrointestinal tract of humans and other animals.

What Role Does Alistipes onderdonkii Play in the Gut Microbiota?

Alistipes onderdonkii is involved in the complex ecosystem of the gut microbiota, contributing to the breakdown of dietary fibers, production of short-chain fatty acids, and modulation of the host's immune system. It helps maintain gut health and balance.

How is Alistipes onderdonkii Detected?

Alistipes onderdonkii can be detected through various methods, including:

• 16S rRNA gene sequencing: This method identifies bacterial species based on their genetic material.

• Metagenomic sequencing: A more comprehensive approach that sequences all the genetic material in a sample to identify and quantify different microbial species.

• Culture-based methods: Growing the bacteria in specific conditions to identify it, though this is less common for Alistipes species.

What Are the Potential Health Implications of Alistipes onderdonkii?

Research on Alistipes onderdonkii is still ongoing, but it has been associated with both positive and negative health effects:

• Positive effects: It may contribute to the production of beneficial metabolites and support a healthy gut environment.

• Negative effects: Some studies suggest a potential association with certain diseases, such as colorectal cancer and inflammatory bowel disease (IBD), though more research is needed to confirm these links.

Can Alistipes onderdonkii Be Used as a Probiotic?

Currently, Alistipes onderdonkii is not used as a probiotic. Probiotics are typically selected for their well-established benefits and safety profiles, and more research is needed to determine whether Alistipes onderdonkii could be beneficial and safe for such use.

How Can I Support a Healthy Gut Microbiota?

To support a healthy gut microbiota, consider the following:

• Diet: Eat a balanced diet rich in fiber, fruits, vegetables, and fermented foods.

• Probiotics and prebiotics: Consume foods and supplements that promote beneficial bacteria.

• Avoid antibiotics when possible: Use antibiotics only when necessary, as they can disrupt the gut microbiota.

• Regular exercise: Physical activity can positively influence gut health.

Where Can I Find More Information About Alistipes onderdonkii and Gut Health?

For more information about Alistipes onderdonkii and gut health, consider consulting:

• Healthcare providers: Medical professionals can provide personalized advice and information.

• Scientific literature: Research articles and reviews on gut microbiota and specific bacterial species.

• Reputable health organizations: Websites of organizations such as the National Institutes of Health (NIH) and the American Gastroenterological Association (AGA).

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