Pharm.D. Doctor of Pharmacy Microbiology and Infectious Diseases 2

Question 1

What is the primary molecular mechanism of methicillin resistance in MRSA?

Accepted Answer

Acquisition of mecA gene encoding altered PBP2a

Answer

MRSA acquires the mecA gene (carried on SCCmec mobile elements), which encodes PBP2a, an altered penicillin-binding protein with very low affinity for all beta-lactam antibiotics.

Question 2

Which antibiotic is the preferred treatment for infections caused by KPC-producing carbapenem-resistant Enterobacteriaceae (CRE)?

Accepted Answer

Ceftazidime-avibactam

Answer

Ceftazidime-avibactam is preferred for KPC-producing CRE because avibactam inhibits serine-based KPC enzymes, restoring ceftazidime's antibacterial activity against resistant organisms.

Question 3

What is the recommended first-line regimen for Helicobacter pylori eradication in regions with low clarithromycin resistance (below 15%)?

Accepted Answer

PPI + amoxicillin + clarithromycin for 14 days

Answer

Clarithromycin-based triple therapy (PPI + amoxicillin + clarithromycin for 14 days) is first-line for H. pylori eradication where clarithromycin resistance rates are below 15%.

Question 4

Which antiviral neuraminidase inhibitor is approved for treatment of both influenza A and B when initiated within 48 hours of symptom onset?

Accepted Answer

Oseltamivir

Answer

Oseltamivir (Tamiflu) is a neuraminidase inhibitor effective against both influenza A and B that reduces symptom duration by approximately one day when initiated within 48 hours of onset.

Question 5

What is the drug of choice for both prophylaxis and treatment of Pneumocystis jirovecii pneumonia (PCP) in HIV-infected patients with CD4 count below 200 cells/μL?

Accepted Answer

Trimethoprim-sulfamethoxazole (TMP-SMX)

Answer

TMP-SMX is the drug of choice for both PCP prophylaxis and treatment, as it inhibits two sequential steps in folate synthesis in P. jirovecii and achieves superior outcomes compared to alternatives.

Pharm.D. Doctor of Pharmacy Practice Test

Pharm.D. Doctor of Pharmacy Practice Test

Pharm.D. Doctor of Pharmacy Microbiology and Infectious Diseases 2