Clinical Knowledge Assessment – Full 150 Q
Set, Answers And Rationales.
2025/2026
1. Which antibiotic class inhibits bacterial cell wall synthesis by
binding to penicillin-binding proteins?
a) Macrolides
b) Beta-lactams
c) Aminoglycosides
d) Fluoroquinolones
Rationale: Beta-lactams inhibit cell wall synthesis by binding to
penicillin-binding proteins, leading to bacterial lysis.
2. Which of the following antibiotics is effective against
Pseudomonas aeruginosa?
a) Amoxicillin
b) Piperacillin-tazobactam
c) Vancomycin
d) Azithromycin
Rationale: Piperacillin-tazobactam has broad-spectrum activity
including Pseudomonas species.
3. A patient develops a rash after starting amoxicillin. The most likely
mechanism is:
a) Direct cytotoxic effect
b) IgE-mediated hypersensitivity
c) Dose-dependent toxicity
d) Microbiome disruption
Rationale: IgE-mediated hypersensitivity is the primary mechanism of
penicillin-induced allergic reactions.
, 4. Which antibiotic is contraindicated in pregnancy due to risk of
tooth discoloration in the fetus?
a) Ceftriaxone
b) Azithromycin
c) Tetracyclines
d) Penicillin
Rationale: Tetracyclines bind to calcium in developing teeth and bones,
causing discoloration and growth inhibition.
5. What is the mechanism of action of aminoglycosides?
a) Inhibit DNA gyrase
b) Inhibit cell wall synthesis
c) Inhibit protein synthesis at the 30S ribosomal subunit
d) Inhibit folate synthesis
Rationale: Aminoglycosides bind to the 30S ribosomal subunit, causing
misreading of mRNA and defective protein synthesis.
6. Which antibiotic is considered first-line treatment for methicillin-
resistant Staphylococcus aureus (MRSA) infections?
a) Cefazolin
b) Amoxicillin
c) Vancomycin
d) Ciprofloxacin
Rationale: Vancomycin is effective against MRSA as it bypasses beta-
lactam resistance mechanisms.
7. Fluoroquinolones primarily act by:
a) Inhibiting ribosomal protein synthesis
b) Disrupting cell membranes
c) Inhibiting DNA gyrase and topoisomerase IV
d) Blocking folate synthesis
,Rationale: Fluoroquinolones inhibit DNA replication enzymes, leading
to bacterial cell death.
8. Which antibiotic is bacteriostatic rather than bactericidal?
a) Penicillin
b) Vancomycin
c) Tetracycline
d) Aminoglycosides
Rationale: Tetracycline inhibits protein synthesis without directly killing
bacteria, making it bacteriostatic.
9. A patient on long-term trimethoprim-sulfamethoxazole therapy
should be monitored for:
a) Nephrotoxicity
b) Hyperkalemia
c) Ototoxicity
d) Tendon rupture
Rationale: Trimethoprim can cause hyperkalemia by inhibiting renal
potassium excretion.
10. Which antibiotic can cause a disulfiram-like reaction when
combined with alcohol?
a) Penicillin
b) Cephalexin
c) Metronidazole
d) Clindamycin
Rationale: Metronidazole inhibits aldehyde dehydrogenase, leading to
acetaldehyde accumulation and reaction with alcohol.
11. Linezolid is effective against:
a) Gram-negative bacteria only
b) Anaerobes only
, c) Gram-positive bacteria including MRSA and VRE
d) Pseudomonas aeruginosa
Rationale: Linezolid inhibits protein synthesis and is active against
resistant Gram-positive organisms.
12. Which antibiotic class carries a risk of tendon rupture?
a) Beta-lactams
b) Macrolides
c) Fluoroquinolones
d) Sulfonamides
Rationale: Fluoroquinolones have been associated with tendonitis and
tendon rupture, especially in older adults.
13. Clindamycin is most commonly associated with which
adverse effect?
a) Nephrotoxicity
b) Hepatitis
c) Clostridioides difficile-associated diarrhea
d) QT prolongation
Rationale: Clindamycin disrupts gut flora, increasing risk of C. difficile
infection.
14. Which antibiotic class is known to prolong the QT interval?
a) Penicillins
b) Aminoglycosides
c) Macrolides
d) Tetracyclines
Rationale: Macrolides such as azithromycin can prolong the QT interval
and predispose to arrhythmias.
Set, Answers And Rationales.
2025/2026
1. Which antibiotic class inhibits bacterial cell wall synthesis by
binding to penicillin-binding proteins?
a) Macrolides
b) Beta-lactams
c) Aminoglycosides
d) Fluoroquinolones
Rationale: Beta-lactams inhibit cell wall synthesis by binding to
penicillin-binding proteins, leading to bacterial lysis.
2. Which of the following antibiotics is effective against
Pseudomonas aeruginosa?
a) Amoxicillin
b) Piperacillin-tazobactam
c) Vancomycin
d) Azithromycin
Rationale: Piperacillin-tazobactam has broad-spectrum activity
including Pseudomonas species.
3. A patient develops a rash after starting amoxicillin. The most likely
mechanism is:
a) Direct cytotoxic effect
b) IgE-mediated hypersensitivity
c) Dose-dependent toxicity
d) Microbiome disruption
Rationale: IgE-mediated hypersensitivity is the primary mechanism of
penicillin-induced allergic reactions.
, 4. Which antibiotic is contraindicated in pregnancy due to risk of
tooth discoloration in the fetus?
a) Ceftriaxone
b) Azithromycin
c) Tetracyclines
d) Penicillin
Rationale: Tetracyclines bind to calcium in developing teeth and bones,
causing discoloration and growth inhibition.
5. What is the mechanism of action of aminoglycosides?
a) Inhibit DNA gyrase
b) Inhibit cell wall synthesis
c) Inhibit protein synthesis at the 30S ribosomal subunit
d) Inhibit folate synthesis
Rationale: Aminoglycosides bind to the 30S ribosomal subunit, causing
misreading of mRNA and defective protein synthesis.
6. Which antibiotic is considered first-line treatment for methicillin-
resistant Staphylococcus aureus (MRSA) infections?
a) Cefazolin
b) Amoxicillin
c) Vancomycin
d) Ciprofloxacin
Rationale: Vancomycin is effective against MRSA as it bypasses beta-
lactam resistance mechanisms.
7. Fluoroquinolones primarily act by:
a) Inhibiting ribosomal protein synthesis
b) Disrupting cell membranes
c) Inhibiting DNA gyrase and topoisomerase IV
d) Blocking folate synthesis
,Rationale: Fluoroquinolones inhibit DNA replication enzymes, leading
to bacterial cell death.
8. Which antibiotic is bacteriostatic rather than bactericidal?
a) Penicillin
b) Vancomycin
c) Tetracycline
d) Aminoglycosides
Rationale: Tetracycline inhibits protein synthesis without directly killing
bacteria, making it bacteriostatic.
9. A patient on long-term trimethoprim-sulfamethoxazole therapy
should be monitored for:
a) Nephrotoxicity
b) Hyperkalemia
c) Ototoxicity
d) Tendon rupture
Rationale: Trimethoprim can cause hyperkalemia by inhibiting renal
potassium excretion.
10. Which antibiotic can cause a disulfiram-like reaction when
combined with alcohol?
a) Penicillin
b) Cephalexin
c) Metronidazole
d) Clindamycin
Rationale: Metronidazole inhibits aldehyde dehydrogenase, leading to
acetaldehyde accumulation and reaction with alcohol.
11. Linezolid is effective against:
a) Gram-negative bacteria only
b) Anaerobes only
, c) Gram-positive bacteria including MRSA and VRE
d) Pseudomonas aeruginosa
Rationale: Linezolid inhibits protein synthesis and is active against
resistant Gram-positive organisms.
12. Which antibiotic class carries a risk of tendon rupture?
a) Beta-lactams
b) Macrolides
c) Fluoroquinolones
d) Sulfonamides
Rationale: Fluoroquinolones have been associated with tendonitis and
tendon rupture, especially in older adults.
13. Clindamycin is most commonly associated with which
adverse effect?
a) Nephrotoxicity
b) Hepatitis
c) Clostridioides difficile-associated diarrhea
d) QT prolongation
Rationale: Clindamycin disrupts gut flora, increasing risk of C. difficile
infection.
14. Which antibiotic class is known to prolong the QT interval?
a) Penicillins
b) Aminoglycosides
c) Macrolides
d) Tetracyclines
Rationale: Macrolides such as azithromycin can prolong the QT interval
and predispose to arrhythmias.
