Microbiology and Infectious Diseases Flashcards
7 cards from real Pharm.D. Doctor of Pharmacy practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Microbiology and Infectious Diseases flashcards as text
Which antibiotic class inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins (PBPs)?
Answer: Beta-lactams
Beta-lactams (penicillins, cephalosporins, carbapenems) inhibit bacterial cell wall synthesis by covalently binding to penicillin-binding proteins, preventing peptidoglycan cross-linking.
What is the primary mechanism of action of fluoroquinolone antibiotics?
Answer: Inhibit DNA gyrase and topoisomerase IV
Fluoroquinolones inhibit DNA gyrase and topoisomerase IV, enzymes essential for bacterial DNA replication and transcription, leading to double-strand DNA breaks and cell death.
Which organism is the most common bacterial cause of community-acquired pneumonia (CAP) in otherwise healthy adults?
Answer: Streptococcus pneumoniae
Streptococcus pneumoniae (pneumococcus) is the most frequently identified bacterial pathogen in community-acquired pneumonia across all age groups.
What is the drug of choice for confirmed methicillin-resistant Staphylococcus aureus (MRSA) bacteremia?
Answer: Vancomycin
Vancomycin is first-line for MRSA bacteremia because MRSA is resistant to beta-lactams, and vancomycin inhibits cell wall synthesis via a different mechanism (binding D-Ala-D-Ala termini).
Which antifungal class inhibits the enzyme lanosterol 14-alpha-demethylase (CYP51), thereby reducing ergosterol synthesis in fungal cells?
Answer: Azoles (e.g., fluconazole)
Azoles inhibit lanosterol 14-alpha-demethylase (CYP51), reducing ergosterol synthesis and disrupting fungal cell membrane integrity, resulting in fungistatic activity.
According to current IDSA/SHEA guidelines, which antibiotic is preferred over oral vancomycin for initial non-severe Clostridioides difficile infection due to lower recurrence rates?
Answer: Fidaxomicin
Fidaxomicin is preferred over oral vancomycin for non-severe CDI due to its narrow spectrum against C. difficile and superior rates of sustained clinical cure with lower recurrence.
Which antibiotic is contraindicated near term in pregnancy due to the risk of 'gray baby syndrome' in neonates?
Answer: Chloramphenicol
Chloramphenicol is contraindicated near term because neonates have immature hepatic glucuronosyltransferase, leading to drug accumulation and gray baby syndrome (cardiovascular collapse).