Question 1

Which of the following is considered part of the resident microbiota of the female reproductive system?

Accepted Answer

Candida and Lactobacillus are both part of the normal resident microbiota of the female reproductive system.

Question 2

During which stage of disease should an infected person be considered contagious?

Accepted Answer

An infected person can be contagious during all stages of a disease, including the incubation period, illness stage, decline stage, and convalescence period, depending on the specific disease.

Question 3

Among the virulence factors produced by Staphylococcus aureus are hemolysin, coagulase, hyaluronidase, and enterotoxin. Which of these factors contribute(s) to the ability of S. aureus to invade the body?

Accepted Answer

Hyaluronidase contributes to the ability of S. aureus to invade the body by breaking down hyaluronic acid, a component of the extracellular matrix.

Question 4

A person licks a needle before injecting a drug into a vein. The person later develops a bacterial infection of the blood. This is an example of

Accepted Answer

Licking the needle introduces bacteria from the mouth (part of the microbiota) into the bloodstream, an unusual location for these bacteria, leading to infection.

Question 5

Diseases that are induced by modern medical procedures are referred to as infections.

Accepted Answer

Iatrogenic diseases are those that are caused by medical procedures or treatments.

Question 6

Vomiting is a common sign of food poisoning. The corresponding symptom would be

Accepted Answer

Nausea is the sensation that often precedes vomiting, making it a corresponding symptom.

Question 7

Which of the following is considered a mechanical vector transmission?

Accepted Answer

Mechanical vector transmission involves the physical transfer of pathogens by a vector without the pathogen undergoing any part of its life cycle within the vector. Cockroaches can physically carry Shigella on their bodies, making them mechanical vectors.

Question 8

A bacterium inhabits the human nasal cavity where it obtains nutrients from secretions. It neither harms nor benefits the host. The relationship is therefore a(n) one.

Accepted Answer

The relationship is commensal because the bacterium benefits by obtaining nutrients without affecting the host positively or negatively.

Question 9

Bacterial contaminants grow in food in a closed container. The food is heated after the container is opened, but a person develops food poisoning after eating it. The bacteria were producing

Accepted Answer

Exotoxins are toxic substances secreted by bacteria that can cause harm even if the bacteria are killed by heat, as they are often heat-stable.

Question 10

Chagasʹ disease is transmitted by a bug with mouthparts that penetrate blood vessels. Which type of exposure does this represent?

Accepted Answer

Chagas' disease is transmitted through the parenteral route as the bug's mouthparts penetrate blood vessels directly, bypassing the skin and mucous membranes.

Question 11

The fungus Pneumocystis jiroveci is found in the lungs of most people in low numbers, but in immunocompromised people it overgrows, resulting in severe respiratory problems. The fungus is best described as

Accepted Answer

Pneumocystis jiroveci is part of the resident microbiota in healthy individuals but can become an opportunistic pathogen in immunocompromised individuals, leading to severe respiratory issues.

Question 12

Symptoms are

Accepted Answer

Symptoms are subjective characteristics of a disease that only the patient can feel, such as pain or fatigue, which cannot be directly observed or measured by others.

Question 13

A protozoan and its resident bacteria invade the body of a worm. The bacteria release toxins and exoenzymes that immobilize and digest the worm, and the protozoan and bacteria absorb the nutrients produced. The relationship between the protozoan and the bacteria would best be described as

Accepted Answer

The relationship between the protozoan and the bacteria is mutualism because both organisms benefit from the association; the bacteria help digest the worm, and both the protozoan and bacteria absorb the nutrients.

Question 14

Which of the following is NOT an example of symbiosis?

Accepted Answer

Symbiosis refers to a close and often long-term interaction between two different biological species. Microbes passing across the placenta to the fetus is not a symbiotic relationship; it is typically a harmful or pathogenic interaction.

Question 15

Which of the following might result in a nosocomial infection (HAI)?

Accepted Answer

The answer of Which of the following might result in...

Question 16

Which of the following is transmitted by the parenteral route?

Accepted Answer

Yellow fever is transmitted by the parenteral route through the bite of an infected mosquito.

Question 17

The close contact between newborns and family members allows them to become with microbes that become established as their microbiota. (Choose the most accurate term.)

Accepted Answer

The answer of The close contact between newborns and family...

Question 18

Which of the following statements regarding the demonstration of the etiology of disease is FALSE?

Accepted Answer

The statement that the suspect agent must be the only potential pathogen present in disease cases is false because multiple pathogens can be present, and the presence of other pathogens does not necessarily rule out the suspect agent as the cause of the disease.

Question 19

Which of the following situations might cause normal microbiota to become opportunistic pathogens?

Accepted Answer

Radiation treatment can weaken the immune system, allowing normal microbiota to exploit the weakened defenses and become opportunistic pathogens.

Question 20

Which of the following situations is NOT a way in which a baby acquires normal microbiota?

Accepted Answer

Microbes do not typically cross the placenta during pregnancy to establish normal microbiota; this is a protective barrier to prevent infections. The other options describe common ways babies acquire microbiota after birth.

Quiz 14: Infection, Infectious Diseases, and Epidemiology