Human Microbiome Overview

Human Microbiome

• The human microbiome is a complex community of microbes living on and inside the human body.
• Different components (bacteria, fungi, viruses, and helminths) exist within the gut microbiome.

Wednesday's Topic: The Human Microbiome

• The human microbiome includes all microorganisms that live on and in humans.
• Studying the human microbiome involves analysing the composition, structure, and function of microbial communities.
• Key questions in this field involve the relationship between the microbiome and human health, the effects of environmental factors, and the impact on disease including obesity and gut-brain axis.

Friday's Topic: Microbiome, Health, and Disease

• The gut microbiome plays a role in obesity.
• Antibiotics, the gut microbiota, and C. difficile are important factors to consider in microbiome health.
• The gut-brain axis connects gut bacteria to brain function.

Today's Topic: Manipulating the Gut Microbiome

• Probiotics are live microorganisms that confer health benefits to the host in adequate amounts.
• The other members of the gut microbiome (bacteria, fungi, viruses, helminths) are also important for therapeutic manipulations and have diverse and complex functions.

The Other Members of the Gut Microbiome

• The gut microbiome has bacterial, fungal, viral (virome), and helminthic (macrobiota) components.
• These populations have immense ranges, and understanding their precise distributions and characteristics is essential for therapeutic microbiome manipulation.

Manipulating the Gut Microbiome with Bacteria (Probiotics)

• Probiotics are live microorganisms, which when administered in adequate amounts, confer health benefits to the host.
• Examples of sources of probiotics could include fermented foods, supplements, or even cultured foods like yogurt.

Current Issues with Probiotics

• Current studies on probiotics may be limited by small or inferior study design, lack of in vivo data or inadequate methods for measuring probiotic effects.
• The probiotic industry is largely unregulated and needs greater regulatory oversight
• Standardizing and validating measures of health benefits is needed.
• Current methods for predicting probiotic functionality in humans are insufficient.
• Missing information about strains, dosage, duration, frequency, timing, indications, and side effects remains a critical gap in knowledge.
• Rare infections associated with probiotics may involve transfer of microbial properties such as antibiotic resistance genes.

Probiotics vs. FMT

• Antibiotics like ciprofloxacin and metronidazole can significantly decrease gut bacterial diversity (in both mice and humans).
• Bi-daily probiotics administration may not restore microbiome diversity as completely as fecal microbiota transplantation (FMT) from the same person
• Mice with a native gut microbiome are not easily colonized by probiotics; however, antibiotics enhance the ability of probiotics to colonize.
• Probiotic colonization is site- and person-specific in humans.
• Probiotics delay gut microbiome reconstitution and metabolism after antibiotic exposure, while FMT from the same person restores microbiome diversity.

Helminths in the Gut Microbiome

• Helminths (worms) are a type of parasitic worm.
• Helminths affect roughly 25% of the world's population.
• A common concern is co-infection.
• Worms can affect the immune system of the host and can increase immunity for specific pathogens. This is also potentially impactful in relation to autoimmune diseases.

The Hygiene Hypothesis and Helminths

• Reduced helminth exposure due to improved hygiene is thought to potentially increase susceptibility to autoimmune diseases.

Phage in the Gut

• Bacteriophages are viruses that infect bacteria.
• Phage populations are dynamic.
• They are present in the gut and may change during health conditions like inflammation or diseases like stunting.
• Phages can change the communities of bacteria, and they can shape microbiome-immune system cross-talk.
• Phages can be integrated in certain bacterial cells and form a unique community called "core phageome."

Phage and Child Stunting

• Stunting (height-for-age) is significantly affected by malnutrition.
• Specific changes in phage communities can occur in the gut based on stunting compared to healthy cases.
• Time for intervention appears linked to the age below 23 months.

General Microbiome Manipulation Considerations

• Both probiotics, prebiotics, helminths and phage should be considered as part of the gut microbiota, and the interactions of these factors contribute to overall gut functionality and health.

Microbiome Study (Research)

• The study investigates how diet affects gut microbes.
• Participation requires a stool sample and dietary information.
• Participants receive compensation (10$).

This quiz explores the intricacies of the human microbiome, including its various components and their roles within the body. It covers topics such as the gut-brain axis, the effects of antibiotics, and the relationship between microbiome health and diseases like obesity. Test your knowledge on how microbial communities impact human health!