Question 1

Which of the following best describes the difference between a virus and a bacterium?

Accepted Answer

Viruses are composed mainly of nucleic acids and sometimes a protein capsid, while bacteria are prokaryotic cells with a rigid cell wall and circular chromosome.

Question 2

Which of the following is an example of mutualism in symbiotic relationships?

Accepted Answer

Bacteria in the human colon producing vitamins for the host.

Question 3

A patient develops pneumonia after being treated with broad-spectrum antibiotics for a urinary tract infection. This is an example of:

Accepted Answer

A superinfection due to disruption of normal microbiota.

Question 4

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

Accepted Answer

Liver via the hepatic artery

Question 5

Which of the following best explains why Streptococcus pneumoniae strains lacking a capsule are avirulent?

Accepted Answer

They are easily recognized and destroyed by host phagocytes.

Question 6

Which of the following is a characteristic of endotoxins?

Accepted Answer

They are part of the outer membrane of Gram-negative bacteria and composed of lipid A.

Question 7

A disease that develops rapidly and runs its course quickly is classified as:

Accepted Answer

Acute

Question 8

Which of the following is the best definition of incidence in epidemiology?

Accepted Answer

The number of new cases of a disease in a given area during a given period of time.

Question 9

Which of the following is an example of vehicle transmission?

Accepted Answer

A person develops cholera after drinking contaminated water.

Question 10

Which of the following best describes the function of bacterial fimbriae?

Accepted Answer

They allow bacteria to adhere to host cells and surfaces, aiding in colonization.

Question 11

A patient is diagnosed with a zoonotic infection. Which of the following is the most likely source of the pathogen?

Accepted Answer

An animal reservoir, such as a dog or rodent

Question 12

Which of the following is a key reason why not all contaminations result in infections?

Accepted Answer

The host's external defenses and immune system can prevent microbial invasion and colonization.

Question 13

Which of the following is a correct statement about Koch’s postulates?

Accepted Answer

They require that the suspected pathogen be isolated and grown in pure culture.

Question 14

Which of the following is an example of an iatrogenic infection?

Accepted Answer

A patient acquires a surgical site infection due to improper sterilization of instruments.

Question 15

Which of the following best describes the role of biofilms in microbial pathogenesis?

Accepted Answer

Biofilms protect microorganisms from host defenses and increase resistance to antibiotics.

Question 16

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

Accepted Answer

It dissolves hyaluronic acid in connective tissue, facilitating the spread of the pathogen.

Question 17

Which of the following is a distinguishing feature of exotoxins compared to endotoxins?

Accepted Answer

Exotoxins are secreted proteins with high toxicity and strong antigenicity.

Question 18

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

Accepted Answer

The disease kills hosts quickly, reducing the chance for transmission to new hosts.

Question 19

Which of the following is the most effective way to reduce healthcare-associated (nosocomial) infections?

Accepted Answer

Handwashing by healthcare workers

Question 20

A patient develops a systemic infection after bacteria spread from a local wound into the bloodstream. What is this process called?

Accepted Answer

Metastatic spread

Infection, Infectious Diseases, and Epidemiology: Foundations of Microbiology

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