Question 1

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

Accepted Answer

The drug should specifically target microbial cells without harming host cells.

Question 2

Which mechanism is NOT a common way bacteria develop resistance to antibiotics?

Accepted Answer

Increasing the rate of host cell division

Question 3

A patient is prescribed a broad-spectrum antibiotic. What is a potential risk associated with this choice?

Accepted Answer

Development of resistance in the normal flora

Question 4

Which of the following drugs acts by inhibiting bacterial cell wall synthesis?

Accepted Answer

Penicillin

Question 5

Why are beta-lactam antibiotics generally more effective against Gram-positive bacteria than Gram-negative bacteria?

Accepted Answer

Gram-positive bacteria have a thicker peptidoglycan layer that is more accessible to beta-lactams.

Question 6

Which test is commonly used to determine the minimum inhibitory concentration (MIC) of an antimicrobial drug?

Accepted Answer

Broth dilution test

Question 7

A new antibiotic is found to block the cross-linking of NAM subunits in peptidoglycan. What is the likely effect on bacterial cells?

Accepted Answer

Cells will lyse due to weakened cell wall integrity.

Question 8

Which of the following is a mechanism by which bacteria can acquire antibiotic resistance genes from other bacteria?

Accepted Answer

Horizontal gene transfer via transformation, transduction, or conjugation

Question 9

Which class of antimicrobial drugs targets the 70S ribosome, inhibiting protein synthesis in bacteria?

Accepted Answer

Aminoglycosides

Question 10

Why are antifungal drugs that target ergosterol in cell membranes selectively toxic to fungi?

Accepted Answer

Human cell membranes contain cholesterol instead of ergosterol.

Question 11

Which of the following is a reason why pharmaceutical companies are reluctant to develop new antibiotics?

Accepted Answer

High development costs and limited profitability due to restricted use

Question 12

A patient with a penicillin allergy is prescribed cephalexin. What is a potential concern?

Accepted Answer

Cross-reactivity due to similar beta-lactam structure

Question 13

Which of the following is a method to limit the development of antibiotic resistance?

Accepted Answer

Completing the full course of prescribed antibiotics

Question 14

Which equation represents the calculation of the minimum inhibitory concentration (MIC) in a broth dilution test?

Accepted Answer

$$MIC = \frac{	ext{Lowest concentration with no visible growth}}{	ext{Volume of broth}}$$

Question 15

Which of the following is an example of cross-resistance?

Accepted Answer

Resistance to multiple aminoglycosides due to a shared mechanism of action

Question 16

Which of the following is a plausible consequence of killing normal flora with broad-spectrum antibiotics?

Accepted Answer

Increased risk of secondary or superinfections

Question 17

Which of the following is NOT a desirable property of an ideal antimicrobial drug?

Accepted Answer

High toxicity to host cells

Question 18

A bacterial strain produces beta-lactamase. What is the most likely outcome when treated with penicillin?

Accepted Answer

The bacteria will degrade penicillin and survive.

Question 19

Which of the following mechanisms allows Mycobacterium tuberculosis to resist fluoroquinolone antibiotics?

Accepted Answer

Production of MfpA protein that mimics DNA and blocks drug binding

Question 20

Which of the following is a reason why antimicrobial resistance is a major public health concern?

Accepted Answer

It leads to the re-emergence of formerly treatable bacterial diseases.

Ch 10 lecture

Study Guide - Practice Questions