Human Microbiome: Microorganisms, Functions, and Pathogen Prevention

What is the human microbiome?

The aggregate of all microorganisms that reside on and within the human body, including bacteria, archaea, fungi, protists, and viruses.

How many microbial cells are approximately in the human body?

Approximately the same number as human cells, around 10^13 to 10^14.

What are the three categories of microbes within the microbiome?

Mutualists (benefit humans), Commensals (neither harm nor benefit humans), and Pathogens (harm humans).

What is Campylobacter?

A genus of bacteria commonly found in the guts of chickens that can cause foodborne diarrhea in humans.

How can Campylobacter be transmitted to humans?

Through the consumption of raw or undercooked meat from infected animals.

What effect does normal gut flora have on broiler chicks regarding Campylobacter?

It significantly reduces the ability of Campylobacter to colonize their gastrointestinal tract.

What is the competitive exclusion principle?

The principle that species compete for limited resources, where mutualists and commensals can prevent pathogen colonization in the gut.

How does E. coli protect against pathogenic strains?

Non-harmful E. coli subspecies consume sugars that pathogenic strains require, preventing their colonization.

What are the two non-harmful subspecies of E. coli mentioned?

E. coli HS and E. coli Nissle.

What is the role of the gut microbiome in human health?

It confers protection from pathogens, influences nutrition and metabolism, trains the immune system, and contributes to brain development and behavior.

What factors can alter the gut microbiome?

Stress, diet, infant feeding methods, pharmaceuticals, geography, and lifecycle stages.

What is the significance of competitive exclusion in the gut?

It prevents pathogen colonization by ensuring normal gut microbes occupy available nutrients and space.

What happens when normal gut microbes are absent?

Pathogenic bacteria can more easily colonize the gut due to lack of competition for nutrients and space.

How many genes do normal gut microbes contribute compared to human cells?

Normal gut microbes contribute approximately 9 million genes compared to about 23,000 genes from human cells.

What is the impact of broiler chicks reared in sterile conditions?

They lack a diverse gut microbiome and are more susceptible to colonization by harmful bacteria like Campylobacter.

What is the relationship between gut microbiome and immune function?

The gut microbiome trains and modulates immune function, helping the body respond to pathogens.

What is the role of competitive exclusion in preventing pathogen colonization?

It relies on competition for limited nutrients and adhesion sites in the gut.

What does the presence of normal gut flora prevent?

It prevents epithelial attachment sites from being available for colonization by enteropathogens.