Pharmacology Antimicrobial Therapy Principles 2

Question 1

A patient with a penicillin allergy requiring treatment for syphilis should receive which alternative?

Accepted Answer

Doxycycline

Answer

Azithromycin

Answer

Ceftriaxone

Answer

Ciprofloxacin

Question 2

Which pharmacokinetic parameter best predicts efficacy of aminoglycoside antibiotics?

Accepted Answer

Peak concentration/MIC ratio

Answer

Time above MIC

Answer

AUC/MIC ratio

Answer

Trough concentration

Question 3

A clinician selects empiric broad-spectrum antibiotics for a patient with septic shock. Once culture results return, the appropriate next step is:

Accepted Answer

De-escalate to the narrowest effective agent

Answer

Continue broad-spectrum therapy for 14 days

Answer

Add a second antibiotic for synergy

Answer

Discontinue antibiotics if cultures are negative

Question 4

Which mechanism underlies MRSA resistance to beta-lactam antibiotics?

Accepted Answer

Acquisition of mecA gene encoding altered PBP2a

Answer

Production of beta-lactamase

Answer

Efflux pump overexpression

Answer

Loss of outer membrane porins

Question 5

A patient develops C. difficile infection after antibiotic therapy. Which drug class most commonly precipitates this complication?

Accepted Answer

Fluoroquinolones

Answer

Aminoglycosides

Answer

Tetracyclines

Answer

Nitrofurantoin

Question 6

Post-antibiotic effect (PAE) refers to which phenomenon?

Accepted Answer

Persistent bactericidal activity after serum drug levels fall below MIC

Answer

Antibiotic accumulation in tissue after dosing ends

Answer

Rebound bacterial growth upon drug discontinuation

Answer

Development of resistance after a short antibiotic course

Question 7

Which antibiotic class acts by inhibiting the 30S ribosomal subunit and is effective against intracellular pathogens like Chlamydia?

Accepted Answer

Tetracyclines

Answer

Macrolides

Answer

Fluoroquinolones

Answer

Carbapenems