Human Microbiome

Question 1

What are the common bacterial species found in the upper respiratory tract? 4

Answer 1

• Haemophilus influenzae
• Staphylococcus epidermidis
• Staphylococcus aureus
• Streptococcus pneumoniae

Question 2

What are the main bacteria found on the skin? 3

Answer 2

1. Staphylococcus epidermidis
2. Staphylococcus aureus
3. Lactobacillus species

Question 3

Which bacteria are commonly found in the colon? 2

Answer 3

Lactobacillus species, Escherichia coli (E. coli)

Question 4

What are commensal microbes?

Answer 4

Microbes that reside on body surfaces or mucosa without harming health

Question 5

How does the microbiome composition vary?

Answer 5

It depends on body site and individual differences

Question 6

What are key functions of the gut microbiome?4

Answer 6

• Stimulates immune system
• Prevents pathogen colonization
• Produces beneficial nutrients (e.g., Vitamin K)
• Metabolizes drugs and toxins

Question 7

How can commensal bacteria cause infections?

Answer 7

By spreading to sterile body parts or increasing in numbers due to disturbances like antibiotics, immune deficiency, or pH imbalance

Question 8

Which bacteria is a common cause of antibiotic-associated diarrhea?

Answer 8

Clostridium difficile

Question 9

How does Clostridium difficile spread?

Answer 9

Person-to-person via the fecal-oral route

Question 10

What treatment can restore gut microbiota balance in Clostridium difficile infections?

Answer 10

Fecal Microbiota Transplantation (FMT)

Question 11

What are Koch’s postulates?

Answer 11

A set of criteria to establish a causal relationship between a microbe and disease

Question 12

What is dysbiosis?

Answer 12

An imbalance in normal gut microbiota leading to harmful effects on the host

Question 13

What are prebiotics?

Answer 13

Non-digestible food ingredients that stimulate beneficial bacterial growth in the gut

Question 14

What are probiotics?

Answer 14

Live beneficial bacteria used as food ingredients to improve health

Question 15

What is pharmacomicrobiomics?

Answer 15

The study of how the microbiome interacts with drugs and influences therapeutic responses

Question 16

Why is microbiome research important in clinical practice?

Answer 16

It can aid in diagnostics, develop new therapies, and influence drug response predictions

Question 17

What is the “One Health” concept in microbiome research?

Answer 17

It emphasizes that the microbiome is key to human health and varies by site and individual.

Question 18

How does the microbiome develop over time?

Answer 18

It evolves from birth, influenced by diet, environment, and lifestyle.

Question 19

How does Clostridium difficile cause disease?

Answer 19

• It forms spores that survive in the environment
• Overgrows in the gut after antibiotic use
• Produces toxins that damage intestinal lining, causing diarrhea

Question 20

What is the role of bile salts in Clostridium difficile infection?

Answer 20

• Primary bile salts enhance C. difficile germination
• Secondary bile salts inhibit C. difficile growth
• Antibiotics reduce secondary bile salts, allowing C. difficile overgrowth

Question 21

What is Fecal Microbiota Transplantation (FMT)?

Answer 21

A treatment that transfers healthy gut bacteria from a donor to restore microbiome balance in patients with recurrent C. difficile infections.

Question 22

What is the limitation of Koch’s postulates in modern microbiology?

Answer 22

They do not account for polymicrobial diseases or microbiome-related conditions where no single pathogen is responsible.

Question 23

How does dysbiosis contribute to chronic diseases?

Answer 23

It alters immune responses, increases inflammation, and disrupts metabolic processes.

Question 24

Name some diseases linked to chronic inflammation and dysbiosis.

Answer 24

Atherosclerosis
Arthritis
Neurodegenerative diseases (e.g., Alzheimer’s, dementia)
Depression

Question 25

What are probiotics used for?

Answer 25

They help restore or maintain a healthy microbiome by introducing beneficial live bacteria.

Question 26

Give an example of a probiotic strain and its benefit.

Answer 26

Lactobacillus species—helps maintain gut and vaginal health.

Question 27

What are the main challenges in microbiome research?

Answer 27

- Reproducibility of studies - Variability between individuals - Translating animal model findings to humans - Distinguishing bacterial vs. viral contributions to disease

Question 28

What is pharmacomicrobiomics?

Answer 28

The study of how the microbiome influences drug metabolism and therapeutic responses.