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

Which of the following is the most important reason why a high therapeutic index (TI) is preferable when choosing an antimicrobial drug?

Accepted Answer

A high TI indicates a wide margin of safety between the toxic dose and the effective dose

Question 3

A patient is prescribed an antibiotic with a minimum inhibitory concentration (MIC) of $$0.5\ \mu g/mL$$ and a toxic dose of $$10\ \mu g/mL. $$What is the therapeutic index (TI) of this drug?

Accepted Answer

$$TI = \frac{10}{0.5} = 20$$

Question 4

Which of the following organisms is NOT typically tested for drug susceptibility before starting antimicrobial therapy?

Accepted Answer

Streptococcus pyogenes

Question 5

A physician is treating a patient with a urinary tract infection caused by E. coli. After broad-spectrum antibiotic therapy, the patient develops a vaginal yeast infection. This is an example of:

Accepted Answer

Superinfection

Question 6

Which of the following mechanisms of antibiotic resistance acts specifically on penicillins and cephalosporins?

Accepted Answer

Enzymes are synthesized, inactivating the drug

Question 7

Which of the following drugs is most selectively toxic to bacteria and least toxic to human cells?

Accepted Answer

A drug that inhibits peptidoglycan cell wall synthesis

Question 8

Which of the following is a broad-spectrum antibiotic?

Accepted Answer

Tetracycline

Question 9

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

Accepted Answer

Ciprofloxacin – DNA unwinding enzymes

Question 10

A patient with a history of penicillin allergy is prescribed a new antibiotic. Shortly after administration, the patient develops hives and respiratory inflammation. This reaction is best described as:

Accepted Answer

Drug allergy

Question 11

Which of the following is NOT a characteristic of the ideal antimicrobial drug?

Accepted Answer

It is microbistatic rather than microbicidal

Question 12

Which of the following is a major adverse effect associated with the use of sulfonamides?

Accepted Answer

Formation of crystals in the kidney and blockage of urine flow

Question 13

Which of the following is a mechanism by which bacteria can acquire resistance to antibiotics?

Accepted Answer

Acquisition of resistance genes via horizontal gene transfer

Question 14

Which of the following is a real-world example of a novel antimicrobial strategy currently under investigation?

Accepted Answer

Using CRISPR delivered by phage vectors to cut resistance genes

Question 15

Which of the following is a correct match between an antimicrobial agent and its category?

Accepted Answer

Amphotericin B – antifungal

Question 16

Which of the following is a major target of antiviral drugs?

Accepted Answer

Inhibition of viral nucleic acid synthesis

Question 17

Why are antiprotozoal and antihelminthic drugs more likely to be toxic to humans than antibacterial drugs?

Accepted Answer

Protozoa and helminths are more similar to human cells than bacteria

Question 18

Which of the following is a recommended strategy for treating biofilm-associated infections?

Accepted Answer

Interrupting quorum sensing pathways

Question 19

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

Accepted Answer

They destroy normal microbiota, allowing opportunistic pathogens to overgrow

Question 20

Which of the following is a correct statement about the Kirby-Bauer disk diffusion test?

Accepted Answer

It measures the zone of inhibition around antibiotic disks to assess susceptibility

Chapter 10: Antimicrobial Treatment – Microbiology Fundamentals

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