Question 1

Which of the following best defines the term 'microbiome' as used in human microbiology?

Accepted Answer

All the genes of the host and the microbiota.

Question 2

Which of the following statements about gut enterotypes is CORRECT?

Accepted Answer

Enterotype #3 is enriched in Ruminococcus.

Question 3

Which of the following is a metabolic contribution of intestinal microorganisms?

Accepted Answer

Synthesis of vitamin K.

Question 4

A newborn delivered by Cesarean section is more likely to have which of the following compared to a vaginally delivered infant?

Accepted Answer

A gut microbiome less similar to the mother’s microbiota.

Question 5

Which of the following is TRUE regarding the relationship between antibiotics and Clostridium difficile infection?

Accepted Answer

Antibiotic use can give C. difficile a growth advantage due to its resistance.

Question 6

Which of the following best describes the function of bacterial capsules in pathogenesis?

Accepted Answer

They facilitate attachment to host tissues and protect bacteria from phagocytosis.

Question 7

Which of the following is a characteristic of highly virulent pathogens based on LD$$_{50}$$ studies?

Accepted Answer

They show little difference in the number of cells required to kill 50% versus 100% of the population.

Question 8

Which enzyme is responsible for breaking down host tissues to facilitate pathogen invasion?

Accepted Answer

Hyaluronidase

Question 9

A patient develops massive inflammation and septic shock after a bloodborne infection. Which term best describes this condition?

Accepted Answer

Septicemia

Question 10

Which of the following statements about exotoxins is CORRECT?

Accepted Answer

Exotoxins are proteins released from the pathogen cell as it grows.

Question 11

Which of the following best explains why probiotic bacteria may help prevent pathogen colonization in the gut?

Accepted Answer

They take up space and nutrients, limiting the ability of pathogens to colonize.

Question 12

Which of the following is a distinguishing feature of superantigen exotoxins?

Accepted Answer

They cause overstimulation of the immune system, potentially leading to shock.

Question 13

Which of the following is TRUE regarding the effect of aging on the human gut microbiome?

Accepted Answer

Aging and frailty are associated with decreased microbial diversity.

Question 14

Which of the following best describes the mechanism of the diphtheria exotoxin?

Accepted Answer

It adds an ADP-ribosyl group to EF-TU, blocking protein synthesis.

Question 15

Which of the following is a correct pairing of enzyme and its function in pathogenesis?

Accepted Answer

Hyaluronidase – breaks down host connective tissue

Question 16

Which of the following statements about endotoxins is CORRECT?

Accepted Answer

Endotoxins are the lipopolysaccharide portion of the Gram-negative cell envelope.

Question 17

Which of the following is a real-world consequence of oral antibiotic use in early life?

Accepted Answer

Increased risk of developing inflammatory bowel disease (IBD)

Question 18

Which of the following best describes an opportunistic infection?

Accepted Answer

An infection caused by organisms that do not cause disease in healthy hosts.

Question 19

Which of the following is a function of enterotoxins?

Accepted Answer

They cause massive secretion of fluid into the intestinal lumen, leading to diarrhea.

Question 20

Which of the following is a plausible outcome of decreased gut microbiome diversity?

Accepted Answer

Higher risk of inflammatory bowel disease (IBD).

Human Microbiota and Infectious Diseases: Structure, Function, and Pathogenesis

Study Guide - Practice Questions