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

Doxycycline is the recommended alternative for penicillin-allergic patients with syphilis when desensitization is not possible.

Question 2

Which pharmacokinetic parameter best predicts efficacy of aminoglycoside antibiotics?

Accepted Answer

Peak concentration/MIC ratio

Answer

Aminoglycosides exhibit concentration-dependent killing, so the peak/MIC ratio (Cmax/MIC) is the primary PK/PD predictor of efficacy.

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

Antibiotic stewardship principles require de-escalation to the narrowest-spectrum agent once culture and sensitivity results are available.

Question 4

Which mechanism underlies MRSA resistance to beta-lactam antibiotics?

Accepted Answer

Acquisition of mecA gene encoding altered PBP2a

Answer

MRSA carries the mecA gene encoding PBP2a, a penicillin-binding protein with low affinity for all beta-lactam antibiotics.

Question 5

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

Accepted Answer

Fluoroquinolones

Answer

Fluoroquinolones, along with clindamycin and broad-spectrum cephalosporins, are among the highest-risk antibiotics for inducing C. difficile infection.

Pharmacology Practice Test

Pharmacology Practice Test

Pharmacology Antimicrobial Therapy Principles 2