Question 1

Which scientist is credited with the discovery of penicillin, the first true antibiotic, and what was the source organism?

Accepted Answer

Alexander Fleming; Penicillium chrysogenum

Question 2

Why are antibiotics generally ineffective against viral infections such as the common cold?

Accepted Answer

Viruses use host cell machinery for replication, making selective toxicity difficult.

Question 3

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

Accepted Answer

They prevent cross-linking of NAM subunits in peptidoglycan, weakening the bacterial cell wall.

Question 4

A patient is prescribed a drug that blocks the synthesis of mycolic acid. Which pathogen is this drug most likely targeting?

Accepted Answer

Mycobacterium tuberculosis

Question 5

Which of the following is a disadvantage of using broad-spectrum antibiotics?

Accepted Answer

They can lead to secondary infections by disrupting normal microbiota.

Question 6

What is the minimum inhibitory concentration (MIC) of an antimicrobial agent?

Accepted Answer

The smallest amount of drug that will inhibit the growth and reproduction of a pathogen.

Question 7

Which of the following mechanisms is NOT a way bacteria can acquire resistance to antimicrobial drugs?

Accepted Answer

Changes in the growth rate

Question 8

A patient develops a severe allergic reaction after taking penicillin, characterized by airway constriction and hives. What is this reaction called?

Accepted Answer

Anaphylactic shock

Question 9

Which of the following drugs acts by inhibiting the enzyme HIV uses to convert its RNA into DNA, and why is it selectively toxic?

Accepted Answer

Reverse transcriptase inhibitors; humans lack reverse transcriptase

Question 10

Which route of administration results in the highest and most immediate concentration of an antimicrobial drug in the bloodstream?

Accepted Answer

Intravenous

Question 11

A hospital-acquired bacterial strain is resistant to at least three different classes of antibiotics. What is this strain called?

Accepted Answer

Multiple-drug-resistant pathogen

Question 12

Which of the following best explains why the largest zone of inhibition in a diffusion susceptibility test does NOT always indicate the best drug for a patient?

Accepted Answer

The drug may not reach effective concentrations at the site of infection.

Question 13

Which of the following is a mechanism by which bacteria can resist the effects of beta-lactam antibiotics?

Accepted Answer

Producing beta-lactamase enzymes that break the beta-lactam ring

Question 14

Which of the following is NOT a recommended strategy to retard the development of antimicrobial resistance?

Accepted Answer

Discontinuing antimicrobials as soon as you feel better

Question 15

Which of the following drugs disrupts the cytoplasmic membrane of fungi by binding to ergosterol?

Accepted Answer

Amphotericin B

Question 16

What is the main reason why quinolones and fluoroquinolones are selectively toxic to bacteria?

Accepted Answer

They inhibit bacterial DNA gyrase, which is not present in human cells.

Question 17

Which of the following best describes the action of sulfonamides?

Accepted Answer

They are competitive inhibitors of PABA, blocking folic acid synthesis.

Question 18

A patient develops a black hairy tongue after taking an antimicrobial drug. Which drug is most likely responsible?

Accepted Answer

Metronidazole

Question 19

Which of the following is the most important characteristic for a successful antimicrobial agent?

Accepted Answer

Selective toxicity

Question 20

Which of the following terms describes the lowest concentration of a drug that kills a particular bacterium?

Accepted Answer

Minimum bactericidal concentration (MBC)

Chpt 10 Controlling Microbial Growth in the Body: Antimicrobial Drugs

Study Guide - Practice Questions

Study Guide - Flashcards