Question 1

Which of the following best describes the principle of selective toxicity in antimicrobial drugs?

Accepted Answer

The drug must be more toxic to the microbe than to the host by exploiting differences in structure or metabolism.

Question 2

A patient is prescribed a broad-spectrum antibiotic. Which of the following is a potential risk associated with this treatment?

Accepted Answer

Increased risk of superinfection due to disruption of normal microbiota.

Question 3

Which mechanism of antimicrobial action is most likely to affect both bacterial and human cells, potentially causing toxicity?

Accepted Answer

Disruption of cytoplasmic membrane

Question 4

Which of the following drugs acts by inhibiting bacterial protein synthesis?

Accepted Answer

Tetracycline

Question 5

A bacterial cell acquires a plasmid encoding an efflux pump. What is the most likely outcome?

Accepted Answer

The cell can actively pump out antibiotics, increasing resistance.

Question 6

Which equation best represents the effect of a bacteriostatic drug on bacterial population over time?

Accepted Answer

$N(t) = N_0$

Question 7

Which of the following is NOT a mechanism by which bacteria can develop antibiotic resistance?

Accepted Answer

Increased uptake of the drug

Question 8

Why are drugs that inhibit cell wall synthesis generally safe for human use?

Accepted Answer

Human cells lack peptidoglycan cell walls.

Question 9

Which of the following best explains why broad-spectrum antibiotics can lead to superinfections?

Accepted Answer

They kill normal flora, allowing opportunistic microbes to proliferate.

Question 10

A patient with influenza is treated with an antiviral drug that blocks viral attachment. Which step of the viral life cycle is being targeted?

Accepted Answer

Entry into host cell

Question 11

Which of the following is a clinical consideration when prescribing antimicrobial drugs?

Accepted Answer

Potential for disruption of normal microbiota

Question 12

Which of the following is an example of synergism in antimicrobial therapy?

Accepted Answer

Using two drugs where one enhances the effect of the other

Question 13

Which of the following is a consequence of horizontal gene transfer among bacteria?

Accepted Answer

Rapid spread of antibiotic resistance genes within a population

Question 14

Which of the following best describes the action of beta-lactam antibiotics?

Accepted Answer

Inhibiting cell wall synthesis by preventing cross-linking of peptidoglycan

Question 15

A hospital patient develops a secondary infection after antibiotic treatment. What is the most likely explanation?

Accepted Answer

The antibiotic killed normal flora, allowing a transient pathogen to infect.

Question 16

Which of the following is a reason why antiviral drugs are more difficult to develop than antibacterial drugs?

Accepted Answer

Viruses use host cell machinery for replication, limiting unique drug targets.

Question 17

Which of the following is a mechanism by which biofilms confer antibiotic resistance?

Accepted Answer

Biofilms physically protect bacteria from antibiotic penetration.

Question 18

Which of the following best describes a superbug?

Accepted Answer

A bacterium resistant to three or more types of antimicrobial agents.

Question 19

Which of the following strategies can help slow the spread of antibiotic resistance?

Accepted Answer

Completing the entire antimicrobial prescription as directed.

Question 20

A patient is treated with ampicillin and a synergistic drug. What is the expected outcome compared to ampicillin alone?

Accepted Answer

Enhanced killing of E. coli due to combined drug action.

Controlling Microbial Growth in the Body: Antimicrobial Drugs

Study Guide - Practice Questions