$$\frac{\text{# of new cases}}{\text{# of people at risk}}$$

Question 1

Which of the following best describes the relationship between Staphylococcus epidermidis and human skin?

Accepted Answer

Commensalism, because the bacterium benefits while the host is unaffected

Question 2

A newborn is generally free of microorganisms until which event introduces normal microbiota?

Accepted Answer

The birth process itself

Question 3

Which of the following is an example of microbial antagonism?

Accepted Answer

Normal microbiota competing for nutrients and space, preventing pathogen colonization

Question 4

A patient receives radiation therapy for cancer and subsequently develops a fungal infection. This is most likely due to:

Accepted Answer

Immune suppression allowing opportunistic pathogens to cause disease

Question 5

Which of the following is NOT a true portal of entry for pathogens?

Accepted Answer

Parenteral route

Question 6

A vector is best defined as:

Accepted Answer

An organism, typically an insect, that transmits a pathogen from one host to another

Question 7

Which of the following is a virulence factor that helps bacteria evade phagocytosis?

Accepted Answer

Formation of a bacterial capsule

Question 8

Which stage of infectious disease is characterized by the most severe signs and symptoms?

Accepted Answer

Illness

Question 9

Which of the following best describes Koch's first postulate?

Accepted Answer

The suspected agent must be found in every case of the disease and absent from healthy hosts

Question 10

Which toxin type is released from the cell walls of dead and dying gram-negative bacteria and can cause serious systemic effects?

Accepted Answer

Endotoxin (Lipid A, LPS layer)

Question 11

A patient with HIV is infected but does not show any symptoms. This state is best described as:

Accepted Answer

Infection

Question 12

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

Accepted Answer

Contaminated water harboring protozoa

Question 13

Which equation correctly calculates the incidence rate in epidemiology?

Accepted Answer

$$\frac{	ext{# of new cases}}{	ext{# of people at risk}}$$

Question 14

Which of the following is a real-world example of an opportunistic infection due to disruption of normal microbiota?

Accepted Answer

Clostridium difficile overgrowth after long-term antibiotic use

Question 15

Which of the following is a correct statement about the parenteral route?

Accepted Answer

It allows pathogens to bypass skin and mucous membranes via direct deposition into tissue

Question 16

Which of the following is a function of coagulase as a virulence factor?

Accepted Answer

Causes blood clotting, providing a hiding place for bacteria

Question 17

Which of the following is an example of a communicable disease?

Accepted Answer

Influenza transmitted from one person to another

Question 18

Which stage of infectious disease is characterized by mild, generalized symptoms such as malaise and muscle aches?

Accepted Answer

Prodromal period

Question 19

Which of the following is a correct example of mutualism?

Accepted Answer

Microbial flora in the human colon help digest polysaccharides

Question 20

Which of the following is a correct definition of prevalence in epidemiology?

Accepted Answer

$$\frac{	ext{# of old and new cases}}{	ext{# of people at risk}}$$

Chapter 14: Infection, Infectious Diseases, and Epidemiology – Study Notes

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