Question 1

Which of the following best describes the relationship between humans and the majority of their gut microbiota?

Accepted Answer

Mutualism, because both the bacteria and the host benefit from the relationship.

Question 2

Which of the following is an example of a nonliving reservoir of infection?

Accepted Answer

Contaminated water containing Vibrio cholerae.

Question 3

A newborn delivered by Caesarian section is at increased risk for which of the following compared to a vaginally delivered infant?

Accepted Answer

Increased risk of developing celiac disease, asthma, and type I diabetes.

Question 4

Which of the following best describes the function of Bifidobacterium longum infantis in breastfed infants?

Accepted Answer

It offers protection from necrotizing enterocolitis by utilizing specific carbohydrates in breast milk.

Question 5

Which of the following is a correct match between a type of symbiotic relationship and an example?

Accepted Answer

Commensalism – Mites in human hair follicles

Question 6

Which of the following conditions can turn normal microbiota into opportunistic pathogens?

Accepted Answer

Immune suppression in the host

Question 7

Which of the following best describes the difference between incidence and prevalence?

Accepted Answer

Incidence is the number of new cases during a period; prevalence is the total number of cases at a given time.

Question 8

A patient is infected with a pathogen that produces hyaluronidase. What is the likely effect of this enzyme?

Accepted Answer

It digests hyaluronic acid, allowing the pathogen to invade deeper tissues.

Question 9

Which of the following is a correct statement about endotoxins?

Accepted Answer

They are part of the outer membrane of Gram-negative bacteria and can cause septicemia.

Question 10

Which of the following best describes the role of the rhizosphere microbiome in plants?

Accepted Answer

It assists in nitrogen cycling and provides organic compounds to the plant.

Question 11

A disease that is constantly present at a low level in a population is best described as:

Accepted Answer

Endemic

Question 12

Which of the following is an example of a biological vector in disease transmission?

Accepted Answer

A mosquito transmitting Plasmodium to a human

Question 13

During which stage of infectious disease is a patient most likely to experience the most severe signs and symptoms?

Accepted Answer

Illness period

Question 14

Which of the following is a sign, rather than a symptom, of disease?

Accepted Answer

Fever

Question 15

A patient develops a secondary infection after being treated for influenza. Which of the following best explains this phenomenon?

Accepted Answer

The initial infection weakened the immune system, allowing opportunistic pathogens to cause disease.

Question 16

Which of the following best explains why an acute disease with a high mortality rate is unlikely to cause a pandemic?

Accepted Answer

High mortality reduces the number of people able to transmit the disease before they die.

Question 17

Which of the following is a correct statement about the acquisition of the human microbiome?

Accepted Answer

The microbiome begins to develop during the birthing process and is influenced by early life exposures.

Question 18

Which of the following is a plausible consequence of disrupting the normal microbiota with broad-spectrum antibiotics?

Accepted Answer

Overgrowth of opportunistic pathogens such as Clostridium difficile.

Question 19

Which of the following best describes the function of metagenomics in microbiology?

Accepted Answer

It is the sequencing of all genetic material from environmental samples to construct a microbiome.

Question 20

Which of the following is the most likely outcome if a person is exposed to a dose of Mycobacterium tuberculosis below the infectious dose (ID)?

Accepted Answer

The person is unlikely to develop disease because the dose is too low to establish infection.

Normal Flora, Symbiosis, and Infectious Disease: Microbiome and Epidemiology

Study Guide - Practice Questions