Q: Which of the following equations correctly represents the therapeutic index (TI) of a drug?

$$TI = \frac{\text{Maximum tolerated dose}}{\text{Minimum effective dose}}$$

Question 1

Which of the following best describes the main goal of antimicrobial chemotherapy?

Accepted Answer

To destroy the infective agent without harming the host’s cells

Question 2

A drug that inhibits the synthesis of peptidoglycan is most effective during which phase of bacterial growth?

Accepted Answer

Exponential growth phase

Question 3

Which of the following is a characteristic of an ideal antimicrobial drug?

Accepted Answer

It is microbicidal rather than microbiostatic

Question 4

Which of the following drugs acts as a competitive inhibitor in the folic acid synthesis pathway in bacteria?

Accepted Answer

Sulfonamides

Question 5

A patient is prescribed a combination of sulfamethoxazole and trimethoprim (TMP-SMX). What is the main advantage of this combination?

Accepted Answer

They target different steps in the same biochemical pathway, resulting in a synergistic effect

Question 6

Which of the following best explains why antiviral drugs are more difficult to design than antibacterial drugs?

Accepted Answer

Viruses rely on host cell machinery for replication

Question 7

Which of the following is a mechanism by which bacteria can develop resistance to antimicrobial drugs?

Accepted Answer

Producing enzymes that inactivate the drug

Question 8

A broad-spectrum antibiotic is most likely to:

Accepted Answer

Affect both gram-positive and gram-negative bacteria

Question 9

Which of the following equations correctly represents the therapeutic index (TI) of a drug?

Accepted Answer

$$TI = \frac{	ext{Maximum tolerated dose}}{	ext{Minimum effective dose}}$$

Question 10

Which of the following is a common source of naturally occurring antibiotics?

Accepted Answer

Streptomyces

Question 11

A patient develops a secondary infection after taking a broad-spectrum antibiotic. What is the most likely explanation?

Accepted Answer

The antibiotic disrupted the normal microbiota, allowing opportunistic pathogens to grow

Question 12

Which of the following drugs is most likely to cause kidney toxicity due to its mechanism of action on bacterial cell membranes?

Accepted Answer

Polymyxins

Question 13

Which of the following best describes the action of beta-lactamases?

Accepted Answer

They inactivate beta-lactam antibiotics by breaking down their structure

Question 14

Which of the following is a reason why selective toxicity is more difficult to achieve with antifungal drugs than with antibacterial drugs?

Accepted Answer

Fungal cells are more similar to human cells than bacterial cells

Question 15

Which of the following is a correct pairing of drug and its target?

Accepted Answer

Aminoglycosides — Protein synthesis

Question 16

A patient is prescribed an antifungal drug that binds to fungal membranes, causing loss of selective permeability. Which drug is most likely prescribed?

Accepted Answer

Amphotericin B

Question 17

Which of the following best describes the mechanism of action of quinolones?

Accepted Answer

Inhibition of nucleic acid synthesis

Question 18

Which of the following is NOT a recommended strategy for combating antimicrobial resistance?

Accepted Answer

Prescribing broad-spectrum antibiotics for all infections

Question 19

Which of the following is a plausible consequence of using a bactericidal drug that targets cell walls in a patient with a gram-negative bacterial infection?

Accepted Answer

A spike in bacterial toxin (LPS) release that can be deadly

Question 20

Which of the following best explains why patients should not demand antibiotics for viral infections?

Accepted Answer

Antibiotics are ineffective against viruses and misuse promotes resistance

Antimicrobial Drugs: Mechanisms, Classes, and Resistance

Study Guide - Practice Questions

Study Guide - Flashcards